FROM THE DIRECTOR As a new arrival at the Institute, let me first pay tribute to both Riccardo Giacconi and Peter Stockman for the manner in which they have integrated the Institute into the overall operation and scientific output of HST, and for the excellent group of people that they have attracted to ST ScI. There are many dedicated individuals who are working with NASA personnel at GSFC and with the GTOs and GOs to ensure that the data flow is maximized and put in the hands of the PIs as quickly as possible. In spite of spherical aberration they have helped see to it that the telescope has been scientifically productive. There are a number of important events coming to the HST project, the most important of which is the planned refurbishment mission, which is scheduled for December of this year. Most aspects of the M&R mission are going very well, with both COSTAR and WFPC2 being shipped to Kennedy Space Flight Center as this is being written. The instruments appear to meet specs, and the mission will hopefully restore HST to full function. Another important event for the entire project is the FY 94 and FY 95 NASA budget projection. NASA, the HST project, and ST ScI are not immune from the general budget problems that have prevailed in science for the past several years, and substantial cuts have been mandated for the project starting on 1 October 1993. The Institute is scheduled to receive a reduction in funding of between 510% for FY 94, with still greater reductions possible for FY 95. For the first time since its inception, ST ScI will be operating with a smaller staff than the previous year. Hoping to achieve the reduced level of effort through attrition, we have imposed a hiring freeze and are not filling vacant positions except in a few critical areas. In spite of this situation, we hope to shield HST users as much as possible from the budget reductions. It appears that the same budget problems may also impact the Guest Observer/Archival Research programs. Even at a reduced level of effort it is important that planning for the future continue, so the Institute will be involved in several studies. The first was requested by NASA, and involves a possible third generation instrument for HST, the Advanced Camera Imager. It is anticipated that the refurbished telescope will produce science of sufficient quality to make third generation instruments compelling. We also intend to work with the community to help define the direction of future space missions. For the present, however, ST ScI remains committed to maximizing the scientific output of the Hubble Space Telescope. This requires constant involvement with the observers and good communication with the astronomical community. We do hope we can continue to be responsive to the needs of our colleagues in providing you with the expertise and facilities which will enable you to achieve first-rate research results with the HST. Bob Williams HST SCIENCE HIGHLIGHTS HOT HST OBSERVATIONS: COMET SHOEMAKER-LEVY 9 (1993E) AND SUPERNOVA SN 1993J Starting with this issue, we will provide concise descriptions of recent observations of objects which, to our arbitrary judgement, are particularly interesting either scientifically or for their technical challenge and can be illustrative of the exceptional results that HST achieves. Our selection for this time are Comet Shoemaker-Levy and SN 1993J. Comet Shoemaker-Levy (1993e) Both the Planetary Camera and the Faint Object Spectrograph were used to make observations of the Comet Shoemaker- Levy 9 (aka, Comet 1993e) on July 1st. This comet broke into many fragments during a close approach to the planet Jupiter in July 1992, but was not discovered until late March 1993. Ground-based observations revealed that the fragments are currently strung out in a line about one arcminute in length. The string of fragments was imaged with the Planetary Camera, and spectra were obtained with the FOS G270H grating and Red Side detector. The images looked great and should provide important information on the sizes of the fragments. The spectroscopic observations were made to search for the UV bands of OH, as the latter provide a sensitive indicator of any ice sublimation occurring in the system. The comet fragments are predicted to collide with Jupiter, near its South Tropical Belt, in July 1994. Although the fragments will probably hit the planet surface on its dark side, the fast rotation of Jupiter will rapidly bring the impact zone into view. The study of this event will hopefully provide a wealth of information on the structure and properties of the Jovian atmosphere. Observations of SN 1993J, the brightest supernova in the Northern Hemisphere since 1937, successfully tested HSTs capabilities to make target-of- opportunity observations on short notice. The difficulty of scheduling these observations was increased because they had to be inserted into the schedule just when the telescope was recovering from a safemode episode (the SADE-1 shut-off, see below). Discovered on 28 March 1993, SN 1993J was first observed with the Goddard High Resolution Spectrograph (GHRS) on April 89 to measure interstellar lines of MgI and MgII, and on April 15 with the Faint Object Spectrograph (FOS) to measure the overall spectrum of the supernova in the range 1600-4800 . Both observations were successful, providing spectra of high and medium resolution of excellent quality. Chris Blades, PI of the first program reports ...some fabulous absorption line profiles. We are looking at the interstellar MgII doublet and MgI in gas from our galactic halo and the parent galaxy using the supernova simply as a background probe. Nino Panagia HST DISCOVERS THE CLOSEST DOUBLE STAR KNOWN AMONG PRE- MAIN SEQUENCE OBJECTS During Cycles 2 and 3 of the Hubble Space Telescope program we are observing with the Fine Guidance Sensor No. 3 (FGS 3) 18 pre-main sequence stars (PMS; GO proposals 3688 and 5041, PI P.L. Bernacca, with U. Bastian, G. Barbaro, R. Pannunzio, M. Badiali, D. Cardini, and A. Emanuele as Co-Is) which are on the HIPPARCOS Input Catalogue (HIC) of the ESA astrometry satellite (ESA SP-1136). Among these, 7 are T Tauri stars and 11 are Herbig Ae/Be objects (HAEBE). The investigation main goals are: a) to detect new binaries in the sample with separations below the detection limit of HIPPARCOS (0.1 arcsec) and down to 0.01 arcsec, and b) to possibly determine the orbits, hence the masses of those pre-main sequence objects found to be angularly close binaries. The satellite HIPPARCOS is providing parallaxes with accuracies in the range 0.0013 arcsec to 0.002 arcsec which, when combined with the FGS measurements, can result in masses good to 25% for the closest systems (< 100 pc). Here we report on the results obtained so far on five HAEBE stars (Table 1). All exposures executed for this program use the TRANS mode capability of FGS 3 (called The Astrometer). This mode samples the interference pattern produced by the Koesters prism interferometer in the FGS. There are actually two such interferometers, one for each FGS axis, which are usually referred to as X and Y axis. When a TRANS mode observation is executed, the FGS instantaneous field-of-view (FOV) scans across the target (with a commandable angular step size) at a fixed 45 angle to the X and Y axes. The result is the aforementioned X and Y interferometric patterns (also called S-curves). All observed fringes were about 1.7 arcsec in length and sampled with an angular step size of 0.008 arcsec. The yellow F550W filter (whose transmission peaks at 550 nm and has a band pass of 75 nm FWHM) was always in place to minimize the effect of residual chromatic aberration within the FGS and to enhance the stellar component from the redder spectrum of the complex nebulosities which are part of our objects. Between 8 and 10 of such scans were executed on each target. Thanks to these multiple scans, the resulting Signal-to-Noise ratio (S/N) of the coadded S-curves used is always > 30. The flaw in the HST main optics and residual aberrations and misalignments within the FGS itself make it impossible to reproduce observed fringes through a model based on first principles applied to Koesters prism interference and pre-launch calibrations. Thus, to determine the signature of a single star (SS) one must resort to in-flight calibrations. We have devoted one orbit of the time allocated to take 10 scans of the standard SS Upgren 69 in NGC 188 (V=9.55). These scans were in everything similar to those on the program stars. The algorithm for the measurement of double stars is based on the comparison, via crosscorrelation, of the observed fringes with high S/N double star templates built from the scans on our certified SS Upgren 69. Previous results based on the above technique indicate that the FGS interferometers are capable of measuring separations good to 30% and position angles to better than 1 deg at 0.01 arcsec separation, which appears to be the resolution limit. This makes the FGS the instrument with the highest angular resolution on board HST. Briefly, assume we know the form of the SS fringe. The hypothesis that the incoming light from two different sources, close by in the sky, is incoherent and the application of the superposition principle yield the expected Double Star (DS) fringe in the form of a linear combination of two SS fringes. This synthetic DS interference pattern depends on the assumed projected separation (dX for the X-axis and dY for the Y-axis) and magnitude difference (Dm) between the primary and the secondary stars, which are the unknown parameters we wish to estimate. In practice, a grid of models is generated by varying dX and Dm. Each DS model is cross-correlated with the observed S- curve and the best-fit model chosen. On-sky separation (s) and position angle (PA) are then computed from the relations s=sqrt(dX*dX+dY*dY) and PA=atan(dY/dX)+PA0. The offset PA0 depends on the orientation of the scan to the direction of the North Celestial Pole and is computed from the spacecraft attitude parameters at the time of observation. The grids of synthetic doubles for the correlation runs were generated with an angular step of (dX or dY) = 0.005 arcsec and a Dm step of 0.07 mag. In all cases we have used the coadded scans for best resolution. The accuracy is ultimately set by the noise sources in the transfer functions. The results of the FGS measurements are summarized as follows. Stars 3401, 28582, and 100628 are single within the resolution limit of our measurements (0.01 arcsec). HIC 53444 (GG Car) is a dubious case as its scans appear noisier than expected for a star of that magnitude. We are looking into the possibility of a pointing error and, in case, hope to be able to repeat the observations in the near future. HIC 35488 has been resolved as double. The best fit results give s = 0.126 0.007 arcsec, Dm = 0.64 0.1 mag, and PA = 63.4 1. HIC 35488 is a new double and the closest visual pair to date among HAEBE stars. As such, it is the best candidate for the first astrometric binary in its class, which would lead to the first astrometric mass determination of an HAEBE PMS object. The FGS X and Y axis coadded fringes of this new double are shown in Fig. 1. The corresponding best fit synthetic S-curves are also shown. For clarity, the best fit models are artificially shifted by +0.1 units along the ordinate axis. It is interesting to note here the very good agreement of the two independent determinations (one for each FGS axis) of the magnitude difference Dm. The best fit values are 0.63 0.07 mag and 0.65 0.07 mag for the interferometer X and Y axis, respectively. In summary, HST has resolved the closest visual double star known to date among HAEBE pre-main sequence stars. This, in combination with data from the astrometric satellite HIPPARCOS and further FGS observations, could provide the first astrometric mass determination among massive newly formed stars, with a chance to place strong limits on the energetics predicted by models of star formation. B. Bucciarelli, M. G. Lattanzi, P. L. Bernacca RESOLVING THE SHELL OF NOVA CYGNI 1992 Nova Cygni 1992 (V1974 Cyg) is one of the brightest classical novae to appear in nearly 20 years. It has been classified as an ONeMg nova. The phenomenon is presently understood to be due to the accumulation of material drawn from a hydrogen-rich companion onto the surface of an ONeMg white dwarf (WD) in an interacting binary system. When enough matter is deposited on the WD, a thermonuclear explosion propels most of its outer layers into the surrounding circumstellar space at high speeds. This mechanism is currently believed to be the primary source of enrichment of the interstellar medium in a number of heavy elements. It is very important to resolve the ejecta from the central star as soon as possible after the outburst, before it has had a chance of modifying its initial conditions and when it is still bright enough to accurately study its dynamics, structure, and composition. Moreover, the angular velocity of the ejecta obtained from high spatial resolution images can be compared with the linear velocity obtained from emission line profiles to yield an accurate distance to the object. The Faint Object Camera (FOC) on HST was used to study the immediate surroundings of Nova Cyg 1992 for this purpose. The instrument was successful in fully resolving, for the first time, the ejecta blown off the WD around 19 Feb. 1992. The observations were carried out on 31 May 1993 with the F/96 camera and the F253M and F278M medium bandpass filters. The HST was in its fine lock pointing mode for the highest possible spatial resolution of 0.06"- 0.07" FWHM. Two exposures of 15 min duration in each filter were obtained within 1.5 hrs of each other. The data were processed in the standard way by the FOC pipeline processing system including large scale flat field and geometric distortion corrections. The measured count rates are all well within the linear part of the detectors intensity transfer function. The Lucy-Richardson restoration algorithm with 40 iterations was applied to these images with the result shown in the figure on page 1 of this Newsletter for the F278M filter data. The prominent ring of emission seen around the central star in this image is a real circumstellar feature and not an artifact of the HST PSF since, at its location, the ring is approximately 40 times brighter than the wings of the central star. The ridge line of the circumstellar feature is well fit by a circle of radius 0.13". The ring does not have a uniform azimuthal surface brightness profile but shows evident knots and inhomogeneities, the brightest features appearing in the NW sector with the faintest in the southern sector. Some knots appear clearly resolved along the ring like the prominent one in the East. The ring thickness is not resolved. The image in this filter bandpass is dominated by emission lines of ionized Neon, Magnesium and Oxygen. The darker regions between the ring and the star are not completely dark. This is especially evident in the NE at position angle (PA) ~ 30 where a bridge of relatively bright emission connects the star to the ring. A fainter feature of this type is discernable in the SW. But even in the darkest areas in the E and W, a residual signal can be detected after the contribution to the count rate there from both the star and the ring is accounted for. Consequently, the circumstellar feature seen in the image on page 1 cannot be a true ring but must be a thin, limb-brightened, inhomogeneous shell of emitting material. The data imply a shell thickness of approximately 6% of the radius, assuming material is distributed at roughly constant density along the two lines of sight. The relatively bright bar at PA 35 and 215 bridging the gap between star and limb could represent either a bipolar flow from the star or, more likely, a density enhancement of the shell in a plane perpendicular to the plane of the sky seen in projection. This could be similar to but fainter than the feature seen in the NW quadrant. The present position of the shell limb at r = 0.13" at day 467 after outburst implies an average angular rate of expansion in that period of 0.00028"/day. Assuming the corresponding expansion velocity to be 1500 km/s from IUE data, the limb on day 467 at the time of observation had reached a radius of 400 70 AU from the star. This also means that Nova Cyg 1992 is located at a distance of 3.2 0.5 kpc, the main source of error being the adopted value of the expansion velocity. The average shell thickness would then be 24 AU, approximately, implying a shell mass of 10-5 - 10-4 Mo. for densities of order 108 - 109 cm-3. In summary, this observation represents the closest look obtained so far at an expanding nova shell so early in its evolution, before it has lost most of the initial conditions impressed on it at outburst. Continuing study of the star and shell at high spatial and spectral resolution in the next six months will be critical in elucidating both the state of the star left over from the outburst and the dynamical evolution of the shell. Especially important will be the determination of the chemical composition of the shell before it mixes with circumstellar material left over from previous episodes of mass loss or accretion. Francesco Paresce HSP OBSERVATIONS OF NOVA CYGNI 1992 Nova Cygni 1992 was discovered on 19 Feb. 1992 (Collins 1992, IAU Circular 5454) at visual magnitude 6.8. The nova continued to brighten by another 2.4 mag, which, given a distance of 2.1 kpc (Hjellming 1993, private communication), corresponds to an absolute magnitude of -7.2. Classical novae are thought to be caused by thermonuclear runaways on massive white dwarfs in close binary systems. The HSP provides the first opportunity to study the short time scale variability of a post-maximum nova in the vacuum ultraviolet. Such studies can provide important new information on the physical processes that drive mass loss during the evolution of a post-maximum active nova. In addition, observations in the vacuum ultraviolet probe the physical conditions near the central luminosity source and can provide important information on the star upon which the explosion occurred. Although we had requested that our observations be obtained during the summer of 1992 when the nova was in its late active phase, they were not scheduled until several months following shell shut-off (1 January 1993). Our observations were made through the 10 arcsec finding aperture and through a broadband ultraviolet filter with sensitivity from 1600 to 3000 . A total of 26,880 measurements were collected with an integration time of 0.1 sec over an approximate 45 mn time period. Fig. 1a (page 7) shows the raw data rebinned to 1 sec time resolution. The overall curvature of the dataset is a common feature in HSP data and is linked to variations in the telescope associated with the orbital period of the HST (Bless et al. 1993, in preparation). Using several sets of HSP data, we have been able to successfully model these long-term fluctuations. Such a model has been applied to the raw Nova Cyg data and the results are depicted in Fig. 1b (page 7). In order to characterize the periodic variability in these data, we have computed the normalized power spectrum using the method described by Buccheri et al. (1993, Astro. Ap., 128, 245) (Fig. 1c, page 7). The data are dominated by two frequencies at 99 cycles/day (14.5 mn) and 152 cycles/day (9.5 mn) each with an amplitude of about 3 millimagnitudes. In addition, there are three other possible periodicities that have a much lower level of significance, but, which have a normalized power consistent with the 99% confidence level. These periods occur at 268, 365, and 864 cycles/day (5.4, 3.9, and 1.7 mn, respectively) and have amplitudes of approximately 1 millimagnitude. We are exploring the possibility that the two-longer term periods are related to the rotation of the white dwarf or perhaps to pulsation modes that have been excited in the compact component of this system. Additional analyses and interpretation of these data are continuing. In addition, a follow-up HSP observation of Nova Cyg is scheduled to occur in September of this year. MaryJane Taylor, University of Wisconsin, Madison THE HST OBSERVATORY PROJECT AND OPERATIONS STATUS Spacecraft Status Since the last Newsletter there have been three spacecraft problems which have affected the observing program. In February the #2 Fine Guidance Sensor (FGS 2) began intermittently failing to acquire guide stars. It was immediately taken off-line and an intensive engineering investigation was begun. Several corrective steps have been taken and we are in the process of recommissioning it for routine use. Late in March, Solar Array Drive Electronics unit 1 (SADE-1) failed. This has resulted in the imposition of additional pointing constraints, at least until the first servicing mission. SADE- 1 replacement is on the list of high priority extravehicular activities (EVA) during the servicing mission. Two magnetometers have also been having intermittent problems, at least one is scheduled for replacement during the servicing mission. Each of these changes to the spacecraft operating rules has impacted the science program in two ways. First, at the time the restriction was placed there was a need to replan the immediate activities in conformance with the new operating rules. This had the potential to decrease the observing efficiency during these periods, but an outstanding effort by the planning and scheduling personnel minimized this impact. A second, long-term effect is that each restriction increases the number of programs which cannot be scheduled. The limitation to two FGSs causes an increase in programs for which guide stars are not available, or are only available for a limited time period. While during the course of a year the entire sky is still available, the solar angle restriction may cause some time-specific observations to be impossible because the target is not accessible during the time desired. ST ScI will work with individual investigators who are affected in any of these ways to seek alternative means of satisfying the scientific objectives of the program. FGS 2: Each FGS has two star selectors, A and B, which are used to position the 5x5 arcsec instantaneous field of view of the FGS within the large overall field. Each star selector has a precision servo motor with a ball bearing about 8 inches in diameter. The optical elements used to position the field of view are mounted inside the bearing, the motor windings are outside. The optical beam passes through the two star selectors in series, A then B. The guide star acquisitions failed when the FGS 2 A star selector occasionally stuck, preventing the system from properly positioning the field of view at the guide star location. The bearing stuck intermittently, causing some, but not all, acquisitions to fail. FGS 2 was shut down and the observing schedule was replanned using only FGSs 1 & 3. A retrospective review of FGS 2 data showed that degradation of the A star selector began long ago, within a year of launch. The first signs of the problem were small glitches in the torque required to slew the star selector. The frequency and amplitude of the glitches have slowly increased over time. In addition, the steady state torque necessary to move the star selector at a given rate has also increased with time. By December of 1992, the glitches were occasionally causing the star selector to stall. By February 1993 it was stalling frequently, at which time we stopped using it. The same retrospective review of the data showed similar symptoms in the A star selectors of the other two FGSs. The symptoms in FGSs 1 & 3 did not seem to progress as fast as in FGS 2. Depending on the symptom being used as a measure, it appeared that FGSs 1 & 3 were several to many months behind FGS 2 in accumulated degradation. None of the B star selectors show these symptoms, although there is a very small increase in the torque required for their operation. The consensus conclusion of the bearing experts is that the degradation was caused by the heavy use of coarse track guidance during the first three years of the mission. During coarse track the star selectors (both A and B) oscillate sinusoidally with a period of one second and by an amplitude which corresponds to a small fraction of a ball spacing in the ball bearing of the star selector. This continued travel back and forth across the same spot is believed to deplete the lubricant in the contact regions of each ball in the bearing, and probably results in the wearing away of small amounts of Teflon from doughnuts which surround every other ball and act as spacers. The Teflon debris then mixes with the lubricant requiring greater torque to drive the bearing and occasionally requiring excess torque to run past a flake. This situation may have been aggravated by the particular lubricant used, which is known now, but not at the time, to be poor in this type of application. The B star selectors are believed not to show this degradation because each orbit they go through a large rotation to place the FGS in default mode for earth occultations. This large rotation is believed to replenish the lubricant. The A star selectors are left where they were during occultations, so they could go many orbits before there is a motion which replenishes the lubricant. Accelerated lifetime tests are being run on spare bearings at LMSC to verify the degradation mechanism and gain insight into the likely lifetime of the flight bearings given their current condition. The analysis of the likely cause of the problem led to the obvious decision to avoid use of coarse track as much as possible. Coarse track had been used about 80% of the time, largely because the spherical aberration degraded fine lock and limited guide stars to brighter than 13.0 mag, and because until recently fine lock was subject to losses of lock at each day/night terminator crossing. At the time, early in the mission, when the decision was made to rely heavily on coarse track for guiding the wear effects on the bearings were not anticipated by the engineering team responsible for the FGS units. Since March we have completely switched to use of fine lock, averaging less than 3% use of coarse track since then. In addition, we are regularly using only a single guide star, rather than a pair, for single orbit snapshot programs. These changes in operational procedures have reduced the accumulation of stress cycles on the bearings by roughly a factor of 1015. Recent trending data for FGSs 1 & 3 indicate that the A star selectors have not gotten worse, and may have improved, since these changes in operational procedures were instituted. Further testing of FGS 2, at lower rotational speeds, indicates that the torque is now much more sensitive to speed than it was before the degradation. At low speeds there is apparently enough torque margin to avoid stalls. The postulated Teflon erosion mechanism is known to be very speed sensitive. The flight software has been modified to reduce by a factor of three the maximum rate at which the star selectors slew. Because of the method of flight software implementation, this will also reduce the average speeds by a factor of three. This is expected to reduce further the degradation rate in FGSs 1 & 3 and may allow us to start using FGS 2 again. FGS 2 is currently being tested by using two pair star acquisitions for some snapshot programs. The first pair uses FGS 2, the second does not. If FGS 2 stalls, then the system will fail the first pair and proceed to the second which should work. In this way the science observations are not put at risk and we will obtain some statistics on the success rate with FGS 2. If FGS 2 works reliably then the plan is to place it back into routine operation. At the present time, we are about half-way through the recertification program and there have been no cases where FGS 2 has stalled. SADE-1 On March 24, HST went into safemode as a result of a failure in one of two redundant SADE units on HST. They are used to control all mechanical motions of the solar arrays, including initial deployment, retraction, and solar array rotations. SADE-1 had been used since launch, with SADE-2 off-line. The safemode entry was prompted by the DF224 checks on the position of the solar arrays. Both arrays were indicated to be outside their legal angle ranges for three successive one second tests, so safemode was entered. At the time of the safing, the HST was carrying out WFPC observations, no slews or solar array motions were in progress. Thus, the indications were that the data provided to the DF224 was in error, rather than the arrays being in the wrong position. Upon safemode entry SADE-1 was disabled and the SADE-2 activated. The software sunpoint mode slewed the telescope about 18 to put the sun on the +V3 axis. The solar arrays were also slewed 18 to put them normal to the sun line. The arrays successfully moved and the power system response was completely nominal. Subsequent tests have proven that a failure in the SADE-1 electronics resulted in erroneous solar array positions being sent to the DF224. Analysis and tests run by ESA, suppliers of the SADEs, has indicated that there is a design problem which could lead to a similar failure in SADE-2. This design problem is planned to be fixed on the replacement unit before the servicing mission. With SADE-1 unusual care must be taken in the event that SADE-2 also fails, since that would then make it impossible to move the arrays. As a result, there have been new pointing restrictions imposed which are intended to guarantee that the arrays stay within the region of their motion which can support all HST operations should they get stuck anywhere within this range. Several considerations have been factored into determining this range. Clearly the arrays must be kept within a range that keeps them from interfering with the process of grappling the HST by the Shuttle. Second, the arrays must be kept within a region which will provide sufficient power for all safemode scenarios without additional array motion. Finally, if a failure should occur in SADE-2 while a solar array rotation is in progress, then the array may run-away for a short period before the failure is detected and motion stopped. This run-away angle must be factored into the determination of the allowable angle. The net result of these considerations is that the solar array normal must now be kept between 90 and 120 of the +V1 direction. In other words, the arrays themselves must be parallel to the telescope tube, or tipped aft by no more than 30. This restriction will ensure that even in the event of a run-away during a SADE-2 failure there will always be sufficient power to support either a +V3 or -V1 to the sun safemode. During normal operations (before the SADE failure) we always positioned the solar arrays to keep the normal to the array as close to the sun as possible. The HST power system has sufficient margin so that this is not strictly required. The power system engineers at GSFC and LMSC have reviewed the current power system performance and have authorized routine use of the telescope with the sun up to 30 from the solar array normal. As an example, if we tip the arrays back to the 120 point we can observe a target which places the sun another 30 aft of the solar arrays. With this technique, we can observe targets which place the sun between 60 and 150 of the target direction. Off-nominal rolls are allowed, but in addition to keeping the sun within 30 of the array normal we must also ensure that the arrays are not shadowed by either the telescope body or the high gain antennas. The performance of the power system will be carefully monitored and small changes in the restrictions may be possible between now and the servicing mission. Magnetometers HST has two magnetometers which provide continuous data on the direction of the earths magnetic field relative to the spacecraft axes. These data are used both by the DF224 flight computer and the safemode computer (when HST enters hardware safemode) to continuously compute the proper current to apply to the on-board magnetic torquer bars. The magnetic torquing counteracts the bulk of the environmental torque on HST and minimizes the amount of angular momentum which must be absorbed by the reaction wheels. The rotation limits on the reaction wheels do not have sufficient range to handle the cyclic orbital torque variations without this assistance from the magnetic torquers. The two magnetometers are located at the forward end of the telescope tube, near the aperture door hinge. Both magnetometers have shown signs of degradation. In one, there are occasional short bursts of saturated data in the V2 axis. In the other, the signal is clipped above a certain level. These effects have not yet been large enough to degrade HST performance. Both symptoms are related to the temperature of the magnetometer, which can get quite cold if it is shadowed on the day side of the orbit. The magnetometers are shadowed by the aft of the telescope if we are observing at sun angles greater than 172. They are shadowed by the aperture door for sun angles between 50 and 57. In order to prevent low temperatures and possible further damage to the magnetometers we are restricted to sun angles between 57 and 172. This restriction is currently moot, as the SADE restriction requires sun angles between 60 and 150. Servicing Mission Preparations for the servicing mission and post-servicing recommissioning of HST continue in parallel with ongoing science operations. As of this time, both WFPC2 and COSTAR have been delivered to GSFC and have undergone successful testing, including operations with the ground system. Only minor changes to the ground system are planned between now and the servicing of HST. The engineering and calibration activities necessary to return HST to scientific operations after servicing are encompassed in the Servicing Mission Observatory Verification (SMOV) plan, and ST ScI, together with the WFPC2 and COSTAR teams, is developing and implementing the proposals necessary to carry these out. Additional details regarding the servicing mission preparations are given elsewhere in this Newsletter. During the servicing mission it is expected that the SADE-1 unit and one of the two magnetometers will be replaced, and that at that time the solar array restrictions associated with the SADE limitation will be removed. The restriction applied for protection of the magnetometers may well be retained in order to protect the performance of the one which is not replaced. Rodger Doxsey and Robert Milkey HST SERVICING MISSION UPDATE AND OVERVIEW OF SERVICING MISSION OBSERVATORY VERIFICATION (SMOV) The first HST servicing mission is still on schedule with the Shuttle launch slated for 2 December 1993, at 4:30 AM, EST. Within the first two days of the mission, the HST will be readied, through a combination of on-board commands and ground commands, for capture by the Shuttle. At approximately 4 AM on Dec. 4, the Shuttle is scheduled to grapple and berth the HST. Starting on day three, the astronauts will begin a series of five EVAs, one per day, during which all the HST upgrades and repairs will be accomplished. As of this writing, the principal activities planned for each EVA are as follows: EVA 1 RSU 2 (Gyros 3 & 4) RSU 3 (Gyros 5 & 6) MSS 1 (Magnetometer 1) EVA 2 Solar Array II EVA 3 WFPC2 GHRS Repair Kit EVA 4 COSTAR ECUs 1 & 3 (Electronic Control Units) EVA 5 SADE-1 MSS 2 Coprocessor Fuse Plug At the end of EVA 5, the new Solar Arrays will be deployed. The current schedule calls for HST to be unberthed at 1:30 AM on Dec 10. At 4:00 AM, the Aperture Door is opened, followed by release of HST at 5:20 AM, a little more than eight days after launch. The Servicing Mission Observatory Verification (SMOV) begins upon release of HST from the Shuttle. Planned for execution over an estimated three-month period, the SMOV has as its primary objectives the recommissioning of the HST for the resumption of science operations in as short a time as possible, and for the publication of Early Release Observations (EROs) to demonstrate the improvement in telescope performance. The SMOV period is divided into three phases: 1) the Real-Time Command Phase, 2) the Health & Safety Stored Program Command (SPC) Phase, and 3) the Science Mission Specification (SMS) Command Phase. The Real-Time Command Phase is the shortest of the three phases, having an expected duration of less than two days. It begins upon HST release from the Shuttle orbiter and consists of those basic operations that normally constitute HST recovery from PSEA Safemode. These operations include, among other things, initialization of the spacecraft, attitude determination and transition to on- board attitude control, gyro bias updates, and uplink of the new ephemeris. Once the first phase of SMOV is completed, the Health & Safety Phase begins with the uplink of the first Health & Safety SPC Load, enabling the initiation of High Gain Antenna (HGA) tracking. The Health & Safety SPC Phase is planned to last about two days, and provides for the completion of the flight software transition to support normal science activities. The third and longest of the SMOV phases is the SMS Command Phase. This phase consists of an extensive series of engineering activation and check-out of the serviced systems, including WFPC2, COSTAR and the COSTAR-corrected SIs, i.e, FOC, FOS, and GHRS. The HST OTA is then collimated, the COSTAR Deployable Optical Bench (DOB) is deployed, and a coordinated program for optical alignment of all the SIs is begun. As each SI achieves fine alignment, a calibration program designed to recommission the SIs as quickly as possible for resumption of science operations is undertaken. At appropriate times after SI alignment and during the calibration phase, Early Release Observations (EROs) will be performed in order to provide images, and possibly spectra, of scientifically interesting targets that clearly demonstrate to the public, the media, and to the scientific community the dramatic improvement in HST performance. The entire SMOV program consists of several dozen interrelated activities that have been designed and documented in a joint effort by NASA/GSFC, the ST ScI, PIs, and IDTs. The ST ScI SMOV preparation team is currently processing 82 proposals for execution during the SMOV period which, under current estimates, will require thirteen weeks for completion. Carl Biagetti SCIENTIFIC INSTRUMENTS WIDE FIELD/PLANETARY CAMERA Decontamination The WF/PC was decontaminated on 2 August 1993 (Day 214) using the standard Flash decontamination procedure with a modification designed to reduce the amount of UV floor removed from the W2 and P6 CCD detectors. The execution of the decontamination procedure was nominal and the desired temperature profiles (peaking between +2 and +6C) were achieved with the exception that the W1 CCD detector only reached -4C. The decision to decontaminate the WF/PC was reached because (1) the buildup of the contamination layer had significantly exceeded prior experience (12 months versus 7 months previously), (2) the system throughput had declined to approximately 50% of its nominal performance in the F336W (U) filter, (3) the level of internal scattered light had increased, (4) the contamination was expected to continue to increase and be unacceptable by the time of the servicing mission, and (5) the instrument required restoration to its clean state prior to the closure photometric calibrations. The decontamination succeeded in restoring WF/PC to nearly the same levels of UV throughput and scattered light as were present following previous decontaminations. While most CCD detectors show basically the same degree of persistent measles as have been present since February 1992, the W1 detector now has a significantly greater quantity of measles contamination. Also, the P5 detector has acquired several tens of more noticeable measles features. Further efforts to remove these contaminants were not attempted in light of the risk of removing the UV Flood. Due to the problems with the HST magnetometers, the UV Flood is irreplaceable and its loss will result in quantum efficiency hysteresis. The stability of the measles features and the flat fields following the decontamination is being monitored and updated information will be placed on STEIS. Flat Fields During Fall 1991, flat field calibrations were obtained from observations of the bright earth for the most extensively used WF/PC filters (the so-called SV flats). Subsequently observations in the remaining filters were obtained. Flat field calibration files have now been created for essentially all of the WF/PC filter set and these are available in the Calibration Data Base. A description of the calibration files is located on the STEIS system (see below) and these files may be obtained from the ST ScI archive. A set of STSDAS tasks (streakflat, normclip, and flagflat) have been used to produce these new flats and are accessible to users who wish to experiment with the production of flat fields. Observers are cautioned that all of the WF/PC flats contain artifacts. Flats for broad band filters are obtained in conjunction with the F122M neutral density filter and have features associated with that filter. All flats (especially between 300 and 600 nm) experience localized changes during decontaminations of the WF/PC. The delta flats may be helpful in correcting for some of these changes. Also, the spectral energy distribution of an astronomical target may be a poor match to that of the sunlit earth. Observers may find it useful to both examine the flat fields which were used to calibrate their data for strong features coincident with their target(s) and to experiment with re-calibration using flats obtained with different filters nearby in wavelength. Dark Current A detailed study of the changes in the dark current over time shows that WF/PC Texas Instruments CCD detectors are standing up well to the radiation environment in the HST orbit. A small number of pixels do show an increase in dark current over time and many of those also show a decline in dark current when the detectors are warmed during decontamination. Generally, only observing programs which co-add many exposures will be affected by the dark pixels. A detailed Instrument Science Report (WF/PC ISR 93-01; J. A. Biretta, C. E. Ritchie, and J. W. MacKenty, The Evolution and Treatment of Hot Pixels in the WF/PC) is available as described below and a listing of pixels with excess dark current is available on STEIS. PSFs The library of observed WF/PC Point Spread Functions now contains more than 580 images in the Calibration Data Base. A listing of these PSFs may be found on STEIS. Closure Calibrations In preparation for the removal of WF/PC from HST during the first servicing mission, certain closure calibrations are being obtained in Cycle 3. In particular, a photometric calibration of all filters on P6 to check their relative throughputs and a repeat of the SV interchip calibrations is being carried out. Also, new flat fields for most of the filters will also be obtained. WF/PC Information on STEIS As the contents of the Calibration Data Base (CDB) continues to increase, observers are reminded that SIB is maintaining memos in the instrument_news/wfpc section of STEIS documenting the availability of pipeline reference files, delta flats, and PSF calibration images. Also, abstracts of technical reports created by the WF/PC group within the Science Instruments Branch at ST ScI are posted on STEIS and these reports are available from the SIB secretary (etkins@stsci.edu) or from John MacKenty. John MacKenty GODDARD HIGH RESOLUTION SPECTROGRAPH Doppler Compensation Problem The peak-to-peak change in the orbital speed of HST is about 15 km/s, significantly more than the resolution of the GHRS (3 km/s in echelle mode). To avoid loss of resolution, the GHRS automatically deflects the spectrum during the observation to compensate for the motion. However, an error was found in the flight software that led it to incorrectly calculate the spectrum shift. That error has now been fixed, so that data obtained after March 1993, should be free of this problem. Known users of the GHRS were notified in April via e-mail of this problem and the means by which they could identify suspect data. In particular, a revised version of the obsum task within calhrs flags spectra that may be affected. Those who need to know more should enter STEIS and look under instrument_news/ghrs. Calibrations Routine instrument calibrations include sensitivity monitoring, dark monitoring and detector calibrations, pulse-height analysis, and wavelength- scale monitoring. Perhaps the two most important calibration programs check the sensitivity and the wavelength scales. Minor changes of amplitude less than about 2% are seen in the sensitivity over time, but there is no overall trend (in particular, there is no decrease). The fluctuations seen are likely due to the focus changes that have been made. A thorough review of wavelength calibrations is currently in progress. Instrument Commanding An algorithm has been written to better center stars in the small science aperture (SSA). As for the spiral search used during an acquisition into the large aperture, SSA/PEAKUP can work with SEARCH-SIZE = 3 or 5. Observations that utilize SSA/PEAKUP show that the algorithm is sound and that the pixel with the highest counts is properly located and moved to the center of the SSA. To further ensure that the center of the stellar PSF is found, SEARCH-SIZE=5 should be used as the default whenever possible. Also, observers should realize that SSA/PEAKUPs are now never to be done by default, in order to reduce confusion. Thus you should explicitly specify an SSA/PEAKUP in your Phase II proposal before any new series of exposures in the small aperture. Addendum 2 to the GHRS Instrument Handbook provides more information; it may be obtained as a PostScript file on STEIS. A LOCATE=EXTENDED option has been written for acquisitions. A test proposal has been written but has been put aside to wait for Cycle 4, when the moons of Jupiter will be available as test targets. Reduction and Analysis Software The obsum task in the hrs package of stsdas was modified in March 1993, to provide observers with information on whether their data may or may not be compromised by the Doppler compensation problem. The mkmultispec task in the hrs package now permits GHRS spectra to be manipulated by noao tasks such as splot without the need for resampling. This task updates the header file of the flux image (the .c1h file) to contain the new multispec nonlinear world coordinate system (WCS) information implemented under IRAF 2.10. The hrs tasks used to combine GHRS FP-SPLIT data have been modified: fpsplit has been replaced by specalign; poffsets has been upgraded; and two new tasks (mkweight and doppoff) have been added. These changes are intended to simplify the processing of FP-SPLIT data. In each case we recommend that you read the help file for each task to learn more. Communications with Observers STEIS The GHRS-related files in STEIS have been cleaned up to remove out-of-date material. A summary of the monthly TIPS (an internal briefing on instrument and telescope status) presentation is now posted to STEIS the day of the TIPS meeting, which is the first Thursday after the first Tuesday of each month. Documentation (in particular, the Instrument Handbook) is now on STEIS as PostScript files and updates to the Handbook are added as necessary. Direct Communication: Urgent communications, such as the news of the Doppler compensation problem, need to reach observers quickly. For those cases we have compiled an e-mail listing of known GHRS users. If you are a user of GHRS data but did not receive the notification of the Doppler problem, we urge you to let us know. Please send a message to soderblom@stsci.edu. Documentation: A data reduction guide is to be written in the summer of 1993. New Instrument Science Reports have been written on the Cycle 3 calibration plan, and the effects of the double LOCATE strategy for LSA centering. The GHRS in Cycle 4 We look forward to a GHRS with improved capabilities in Cycle 4 because of COSTAR and the GHRS Repair Kit. COSTARs optics will provide an essentially diffraction-limited image at the GHRS entrance apertures. The GHRS Repair Kit should allow Sides 1 and 2 of the instrument to communicate independently with the spacecraft, thereby allowing Side 1 to be revived without risk to Side 2. The Side 1 of the GHRS includes detector D1 (with a CeI photocathode) and gratings G140L, G140M, and Echelle-A. If all goes well, we expect to have Side 1 available for scientific observations no later than the second half of Cycle 4. Both Side 1 and Side 2 will require substantial recalibration after the Servicing Mission. Of the proposals received for Cycle 4, 24% request use of the GHRS, essentially the same percentage as in Cycle 3 (which was 25%). Of the GHRS proposals, 25% request use of Side 1 capabilities, despite restrictive rules in such cases. This continued demand for the GHRS at a time when fixes to HST emphasize the cameras underscores the importance of ultraviolet spectroscopy to the astronomical community, and the requests for Side 1 likewise reinforce the importance of the shorter wavelengths for astrophysics. We look forward to a productive Cycle 4. David Soderblom FAINT OBJECT CAMERA Performance of the F/96 relay continues to be nominal. The F/48 camera section was successfully powered up on June 17 but the intensifier stage remains off for the time being. An observing campaign of duration 1 - 2 days using the F/48 side will be attempted in the fall with one calibration proposal consisting of absolute response determination at various wavelengths with a standard star and several GO programs that are best performed with the large field of the F/48 relay. It is not expected that this relay will be turned on again before the servicing mission regardless of the results of the fall campaign. Right after the servicing mission, the F/48 side will be exercised again with long slit programs exclusively to take advantage of this unique capability. Regular operations might resume in Cycle 6 and beyond only if the long slit programs have shown that the detector is functioning properly. The FOC team has continued actively monitoring and calibrating the F/96 relay in order to refine our understanding of the FOC and to prepare for the critical tasks ahead with COSTAR. The latest results of this work have been summarized in a series of SPIE papers in press and available as the ST ScI preprint #751. This preprint contains important information on the recently measured in-flight performance of the FOC and its predicted performance with COSTAR in place. In addition, the accuracy and practical utility of image restoration techniques with the FOC is exhaustively and critically analyzed especially in view of the known temporal variations of the system PSF. More details are also available to the interested reader in a series of Instrument Science Reports, the most recent being those listed in the table below. Finally, we note that the expected response of the FOC+ COSTAR system has been entered into CDBS for use with SYNPHOT and the calibration pipeline. The FOC Simulator FOCSIM has also been updated for this purpose. Francesco Paresce FINE GUIDANCE SENSOR INSTRUMENT REPORT We are pleased to report that the major calibrations for the Fine Guidance Sensors are proceeding smoothly. Our reduction of the data proceeds apace too after a modification of the POSitional Mode observation processing software to conform to the change in the on-board velocity aberration made last Spring. The most progress has been made on the OPTICAL FIELD ANGLE DISTORTION CALIBRATION. The goal of this calibration is to determine the optical field angle distortions of the astrometer FGS, the unit in radial bay #3, to within a scale factor of order unity, with a level of precision and accuracy sufficient to support an overall astrometry error budget of better than 0.005" rms. The solutions for the distortion function will be entered into the Project Data Base. Thus, GTO and GO FGS POSitional Mode observations can now be reduced for the OFAD. The galactic cluster M35 = NGC 2168 was the target; it is the same target used for the Long-Term Stability test observations. The Space Telescope Astrometry Team has completed their investigation of the OFAD measurements. The milli-arcsec level of calibration can be achieved over the majority of the astrometer field-of-view. The successful completion of the OFAD calibration requires that it be performed in association with the HIPPARCOS PLATE SCALE discussed below. The HIPPARCOS PLATE SCALE CALIBRATION purpose is to calibrate the plate scale in the astrometer FGS in association with the Optical Field Angle Distortion calibration. This is especially important for FGS POSitional Mode observations. It uses pairs of stars observed by the ESA astrometry satellite HIPPARCOS. Cross filter calibration is included too. Note that this test, unlike the INTERMEDIATE PLATE SCALE CALIBRATION, provides an average determination of the plate scale in the large. Because this test is very difficult to schedule we have budgeted for a maximum of three repeats. Finally, star selection is now completed. Note that this calibration supplants the MOVING TARGET PLATE SCALE CALIBRATION. Independently, Colin Cox and Matt Lallo of SOB have completed their mini- OFAD-based analysis utilizing the M35 OFAD measurements. This has lead to a successful mini-OFAD algorithm which is much simpler than the original Perkin-Elmer model without sacrificing any precision. Using the same data yet once more has provided us with a photometric calibration of the astrometer FGS too. The results on the photometry are being prepared for publication. A related, but different POS Mode calibration is that of INTERMEDIATE PLATE SCALE. The primary goal of this proposal is to calibrate the plate scale in the central region of the astrometer FGS. This is the most important section of the FGS field-of-view for annual parallax work. Note that, in contrast to the OFAD- related Plate Scale calibration (i.e., the HIPPARCOS PLATE SCALE CALIBRATION), the intent of this set of observations is to ascertain the small- scale variations in the plate scale. To do so, it uses the asterism observed by the ESA astrometry satellite HIPPARCOS especially for this purpose. Cross filter calibration is included too. We have not neglected TRANSfer Mode observing. The BINARY PLATE SCALE CYCLE CALIBRATION, to calibrate the plate scale for binary star observations in the central region of the astrometer FGS, is already executing. Five targets will be observed at three different positions. This is essential for supporting GO and GTO observations of double stars. Cross filter calibrations are included too. A related calibration proposal is the SEVEN POINTS OF LIGHT CALIBRATION. This will characterize the FGS Transfer Function, at seven positions within the astrometer FGS, to determine TRANSfer Mode (i.e., binary star), POSitional Mode, angular diameter, and engineering-related Guide Star acquisition and Fine Lock maintenance parameters. In addition, this calibration provides Fine Lock to Coarse Track offsets, cross-filter calibrations, and an update of the FGS photometric calibration. These seven positions are the same ones that have a high degree of overlap with the various other N points of light tests. Finally, we have very good news from the last Instrument Scientist FGS Calibrationthat of the TIME EXPOSURE CALIBRATION IN HIGH BACKGROUND FIELDS. This calibration proposal has executed successfully with most of the targets showing high quality Transfer Functions. This proves that high spatial resolution capability implicit in the FGS Koesters prism interferometer can be exploited by GOs even in fields with high backgrounds such as HII regions, planetary nebulae, young star-forming regions, and so forth. The complete reduction of the data with the Institutes TRANSfer Mode reduction pipeline is in process. A calibration that we had wanted to perform, that of MINOR PLANET ANGULAR DIAMETER, will be executed instead as a Cycle 3 Supplemental General Observer program! The primary goal of this proposal is to demonstrate and calibrate the capability of the FGSs to perform absolute angular diameter measurements of minor planets larger than 15 mas. Three asteroids of different, known, angular sizes will be observed in the center of the astrometer FGS. Speaking of GOs, with the assistance of visiting General Observers the Institutes POSitional Mode observation processing software has been overhauled. It is now a little more user friendly, provides additional information regarding the prepared data, and is being reconfigured (as time permits) to move more in these two directions. GOs will also receive a boost from the FGS Chapter of the Institutes One Book which discusses the instrument, how the instrument is used, and how the data reduction software for both POS and TRANSfer Mode was constructed and works. Larry Taff and Mario Lattanzi NEWS FOR HST OBSERVERS AND PROPOSERS CYCLE 4 PROPOSAL REVIEW COMPLETED The General Observer proposal deadline for Cycle 4 of HST, the first with the refurbished instruments, was 14 May 1993. Six Subdiscipline Panels and the cross-discipline Telescope Allocation Committee met at the ST ScI during July 1923 to review the 501 GO, Snapshot, and Archival Research proposals received, and the TAC recommendations were reviewed by the ST ScI Director the following week. Notifications of the outcomes were mailed to the proposers in mid-August. The accompanying tables present the complete memberships of the Cycle 4 Panels and TAC, a listing of the approved (High and Medium priority) programs, and summary statistics of the review results. We are especially grateful to the Cycle 4 reviewers for their commitment to community service by assisting with this review during the summer. For completeness, the membership of a special Panel which reviewed AR proposals received for the supplementary solicitation with deadline 1 February 1993, and the approved programs from that review, are also listed separately. Cycle 4 will have a duration of 15 months beginning three months after the HST servicing mission. The available spacecraft time was calculated on the basis of 40% efficiency, and the fraction of time committed to Guaranteed Time Observers is smaller than in past cycles. As a result of these three factors, the available GO time and the number of approved programs are substantially larger than in previous reviews. About 2500 hrs of spacecraft time will be available for GO observations in Cycle 4, after subtraction of allotments for calibration and engineering, repeat observations, Directors Discretionary time, and the GTO time. Of this available time, nominally one-third was assigned High scheduling priority and two-thirds Medium priority; the distinction applies primarily to the level of planning resources which may be available to support complex or inefficient programs. Both categories are considered as approved, but it will be advantageous for those with Medium priority to simplify their Phase II specifications insofar as possible. In addition, a Supplemental priority pool comprising a 50% oversubscription of the available GO time was selected. These latter programs will proceed to Phase II with a later deadline than those of High and Medium priority, but will then constitute an inactive pool for expeditious implementation in case of contingencies which may prevent execution of some High or Medium programs. In that regard, it should be noted that systematic duplication and technical feasibility reviews were not possible in Phase I of Cycle 4, due to the accelerated schedule required by the servicing mission. Such reviews will be conducted for approved programs in Phase II, and conflicting or infeasible observations may need to be eliminated at that time. All approved proposers are advised to check their Phase II specifications against the protected GTO programs listed in STEIS, or consult with ST ScI technical staff in difficult cases, in order to avoid unpleasant surprises later. The Cycle 4 review statistics show that the extragalactic areas are relatively more prominent in both requests and allocations than in prior cycles (similarly to the original, pre-launch Cycle 1 results), as might be expected given the prospect of an optically repaired HST. The Cool Stars subdiscipline is also heavily subscribed; here the effect is due to the inclusion of population studies of distant, resolved systems in this Panel, which also strongly require the refurbished capabilities. A related technical point is worth mentioning here, namely that on the initiative of the Cool Stars Panel, supported by ST ScI and the WFPC2 Team, it is strongly recommended that the F814W filter be selected to define the I band by all programs in Cycle 4, to enhance the homogeneity and calibration accuracy of the resulting analyses. The Cycle 4 Phase II deadline is 30 September 1993 for High and Medium priority programs, and 15 November for Supplemental programs. Looking further ahead, given a nominal servicing mission with launch in early December, the Cycle 5 Call for Proposals will be issued in May 1994, followed by a deadline in July and review during September. This schedule will permit the early results of the refurbishment to be taken into account in the Cycle 5 solicitation, and indeed that is the reason for the extended duration of Cycle 4. Nolan Walborn & Lisa Spurrier POST-OBSERVATION GO SUPPORT The Research Support Branch (RSB) at ST ScI is responsible for post- observation General Observer (GO) support. While most GOs are familiar with the pre-observation support provided by the User Support Branch (USB), GOs should also be aware of the resources that RSB has to offer. RSB provides data analysis support for both visiting and remote GOs who have received their HST data. RSB encourages all HST GOs (especially first time GOs) to visit the Institute at least once to learn how to analyze their data. A Science Data Analyst (SDA) is assigned to each visiting GO and is available to help the GO throughout the entire visit. Our staff of SDAs is very knowledgeable about all aspects of HST data and can answer questions that GOs typically have. During the visit, the SDA serves as the prime contact for the GO, acts as a tutor for the GO, and can also arrange meetings with the instrument scientists or refer the GO to other staff experts in a variety of subjects. SDAs can provide tutorials in UNIX, IRAF, and STSDAS if necessary. They can also teach GOs about Routine Science Data Processing (RSDP), re-calibration, deconvolution, and post-reduction analysis for each of the instruments. A typical visit lasts about a week, but if the GO is unfamiliar with IRAF or STSDAS, we recommend a longer visit. Prior to a visit, the SDA Coordinator (Krista Rudloff, rudloff@stsci.edu, 410-338-5013) assigns an SDA to the GO and sets up a temporary computer account for the GO to use. The SDA Coordinator also contacts the GO to assess his/her needs and goals, and with proper authorization, will load the data (within reasonable volume limits) that the GO wishes to work with during the visit. The assigned SDA prepares for the visit by checking that the account and all hardware and software are functioning properly, as well as checking the quality of the GOs data. This allows the SDA to foresee possible problems or additional needs. Due to this thorough preparation, we request two weeks advance notice for a visit. Data analysis support can also be obtained remotely. Remote GOs are encouraged to call or e-mail RSB with questions they have about any of the topics discussed above. If you have questions about the analysis of your HST data, or would like to arrange a visit, you can contact RSB via e-mail (analysis@stsci.edu) or phone (410-338-1082). Krista Rudloff and Meg Urry ITEMS OF INTEREST FOR FOS USERS Instrument Status The FOS is working well and observations are proceeding normally. GOs have been advised to change their target acquisition strategy from binary search to the more simple peak-up acquisitions, with the result that most acquisitions are succeeding with no difficulties. A small drift in the blue side ybase value, the parameter that controls the location of the spectrum on the diode array, has been found by Koratkar and Taylor (instrument science report is in preparation). If verified, this drift may account for some of the decrease in blue side sensitivity that was reported in CAL/FOS-084 (Bohlin & Neill). The FOS appears to be in very good shape for heading into the refurbishment mission. FOS Weekly Meeting To facilitate the resolution of questions regarding the use of the FOS, a weekly meeting is now held with FOS Instrument Scientists (A. Kinney, T. Keyes, A. Koratkar), the FOS Scientist (I. Evans), the FOS Technical Assistant (C. Taylor), the FOS engineer (T. Wheeler), the FOS commander (D. Chance), the FOS programmer (H. Bushouse), and the FOS Science Data Analyst (J. Christensen, M. Sahi). Forward relevant questions to any of these people, and your questions will be put on the agenda for the weekly Tuesday FOS meeting. FOS Flat Fields Good quality superflats (generally agreed to be highly desirable for most applications) are now available in the pipeline for the blue side (see CAL/FOS- 088 by Lindler, Bohlin, Hartig, and Keyes for a detailed description of the production of superflats). However, the currently available red-side superflats suffer from ringing and are thus not suitable for the pipeline, but have been placed on STEIS in the directory /cdbs/yref. The redside superflats will be taken again in a manner so as to avoid ringing, and are being prepared for observations but are not yet on the schedule. As is well documented in CAL/FOS-075, the redside flats (especially G190H, G160L, and G270H) show significant wavelength structure, and are variable, at least at the earliest epochs. To aid in the reduction of FOS data, T. Keyes and C. Taylor have compiled a reference guide to flat fields, listing delivered flat fields and the epoch for which they should be used (Keyes and Taylor, CAL/FOS-090). This Instrument Science Report is available on STEIS in the directory /cdbs/yref. The flat field summary tables are available on /instrument_news/fos, and are called flat_field_tables_apr93.ps (for the postcript file) and flat_field_tables_apr 93.asc (for the ASCII files). A similar report (Keyes and Taylor, CAL/FOS-093) is available for FOS Inverse Sensitivity Reference files. The red side will be monitored in Cycle 3, both through the small (0.2" x 1.4" ) and the large (4.3" x 1.4") apertures (see Keyes and Koratkar, CAL/FOS-094 for a summary of the Cycle 3 FOS calibration plan). FOS Line Spread Functions and Point Spread Functions The FOS Line Spread Functions for the current telescope have been computed and made available on STEIS (ST ScI Electronic Information Service, see this Newsletter) by Ian Evans. They are in the form of postscript files in the directory instrument_news/fos/fos_lsfs. The postscript file fos_lsfs.ps contains theoretical FOS line spread functions computed from TIM point spread function models (Telescope Image Modeling, see Hasan 1992 ST ScI Newsletter, Vol. 9, No. 2, page 22). Pre-COSTAR LSFs are plotted for each detector and aperture combination at five wavelengths (1400 , 2000 , 2800 , 4000 , and 5000 for the blue side, 2000 , 2800 , 4000 , 5600 , and 7400 for the red side) corresponding approximately to the effective central wavelengths for the G130H, G190H, G270H, G400H, G570H, and G780H gratings, respectively. The LSFs are computed for a point source that is perfectly centered in the aperture. They are normalized to a peak throughput of 1.0, and are plotted as a function of both number of diodes and microns in X from the aperture center. The pre-COSTAR Point Spread Functions for FOS have also been simulated by Evans through the use of TIM, but they are too large to be made available on STEIS. They will soon be made available through the DMF (Data Management Facility, i.e., starcat). Anne L. Kinney WFPC2 NEWS Status WFPC2 passed its thermal vacuum testing at JPL and integration testing at Goddard Space Flight Center with flying colors. In particular it demonstrated its UV capability, and optical correction of the HST aberration. The only significant changes resulting from these tests have been a change in the thermal blanket on the instrument in order to ensure that it fits into HST correctly, a change in the timing of the commanding to the filter wheel, and a minor change in the use of the shutter blades (so that an exposure is always ended with the opposite blade to that which started it even in anomalous situations). None of these changes affect the way general observers should plan to use the instrument. In addition, a wealth of calibration and optical data was obtained which is now being processed ready to support your observations. The following sections update the relevant sections in the Handbook, and should be referred to in preparing your phase II proposals. Choice Of Broad Band Filters A number of different choices are possible on WFPC2 in order to approximate the Johnson Cousins system typically used in ground based observing. These choices differ in throughput, wavelength fidelity, color transformability and cosmetics. The science program as a whole clearly benefits if a standard set for broad band photometry can be agreed upon by the community. This will allow theoretical isochrones and other models to be published in the standard system, and allow easy ready comparison of the results from different observers. Furthermore although all filters will be calibrated photometrically and with flat fields, a core set must be chosen for monitoring the instrument both photometrically and in imaging performance. There is a substantial consensus between the accepted cycle 4 GO programs, the WFPC 1 and 2 science teams, and the Medium Deep Survey key project. However there is some dispersion particularly in the choice for an I passband. In the case of the cool stars TAC panel for cycle 4, the accepted programs are mandated to use a standard system, unless the proposer is able to provide compelling scientific reasons for a different choice. All GOs are strongly encouraged to use F336W, F439W, F555W, F675W, and F814W as approximate equivalents to Johnson Cousins U, B, V, R, I passbands. These filters will form the basis for a WFPC2 broad band photometric system. Note that the WFPC2 handbook listed F569W as a best choice for a V bandpass, and F791W for the I bandbass. The handbook choices are marginally better approximations to the Johnson Cousins passbands, but are not as efficient as the preferred filters. The thermal vacuum results also indicate that some dust is present on F791W, and this affects the flatfield. As can be seen from Figs. 1-5 the preferred set is accurately transformable with the exception of the U bandpass which is not particularly well simulated by any choice. Observers should consider the use of F300W in preference to F336W for detecting hot stars. These Figures can be compared to Figures 6.1 and 6.2 in the WFPC2 handbook. An edited summary of the TAC Cool Star Panel recommendation is as follows: Cycle 4 will see the execution of several imaging programs which involve color-magnitude photometry of old stellar systems (globular clusters and dwarf galaxies). These individual programs are highly complementary to one another, and will have a major impact on our understanding of the chronology of the early Milky Way Galaxy and its satellites. The cumulative impact of these programs will be very much like that of a Large/Key Project in both size and scientific scope. Much of the scientific value of the combined programs will come after each is individually complete and when the color-magnitude data are directly compared, to produce discussions of the relative ages, metallicities, and other properties of the stellar systems concerned. In view of this, the Panel regards it as essential that the different observational groups use the SAME FILTERS wherever feasible, and thus remove any potential difficulties later in transforming between different photometric systems. Most of the programs listed above intend to use the (V,I) bandpasses, but not all are requesting the same filters to define those bands. The Panels opinion is that these filter choices should be MANDATORY. That is, all the programs must use the filters as listed above unless they can make a very strong scientific case to the contrary to the Director during the Phase II preparations. Redleak The handbook did not give information on the redleak in F336W. It is very similar to F300W, and is given here in Table 1. Woods Filters In Thermal Vacuum testing, the two Woods filters (F160AW and F160BW) performed well and were stable. F160AW however does show evidence for pinholes, which cause excessive redleak in some parts of its field. Therefore the preferred filter for far UV imaging with minimal redleak in WFPC2 is F160BW. F157W which is mentioned in the handbook as a possible backup filter to the Woods filters will not be flown. Polarizer At the time of the call for proposals, it was not clear that the option to partially rotate the filters in WFPC2 would be available in time for Cycle 4 GOs. It is now expected that the required processing and commanding software changes will be in place, so GOs are free to use these modes in their phase II proposals. In addition, it became clear from a number of GO inquiries that it was desirable to have additional partial rotations available for the polarizer quad filter in order to enable polarimetry in the PC and in order to allow simultaneous measurements at several polarization angles in the WF cameras. This enhancement will also be supported for cycle 4. The new partial rotation angles (in addition to the -33 rotation already planned) are -18 and +15. The corresponding apertures and filter elements are defined in the revised phase II proposal instructions that will be distributed to successful Cycle 4 GOs and in an instrument science report that is available on request. GOs that are planning to use the polarizers are encouraged to contact the WFPC2 instrument scientists to help ensure that their program is well matched to the planned calibrations. The planned modes are summarized in Table 2. Note that an appropriate aperture or POS-TARG should be used with each partial rotation because in all cases the unvignetted field does not cover the entire chip. Wavefront Quality The conclusion of the extensive optical testing in thermal vacuum is that the cameras are well corrected to within the specifications. The measured wavefront errors in the four cameras were 1/30, 1/17, 1/40, and 1/21 waves at 6328. The dominant problem is a small difference in focus between the four cameras. The actuated fold mirrors and pickoff mirror mechanism performed flawlessly in correcting residual coma aberrations in the image, and enabled us to test the on-orbit alignment procedures. There is some evidence that the images are not as sharp as expected despite the good wavefront quality. The decrease in sharpness corresponds to a loss in limiting magnitude of about 0.3 magnitudes in the WF cameras, and much less decrease in the PC. It may be caused by CCD MTF imperfections, and is still under investigation. Quantum Efficiency The thermal vacuum testing confirmed the throughput estimates in the handbook for wavelengths longward of 2000 as illustrated in Figure 5. A comparison of these throughput values with those available from the WF/PC-1 IDT SV report indicates that WFPC-2 is a factor of a little under 2 less sensitive than WF/PC-1 (because its chips are not thinned). For a given background level, on an isolated point source WFPC2 would be about 2 times more sensitive than WF/PC-1 because of the improved PSF. However, WFPC2 has an intrinsically much lower equivalent background level (by a factor of 2 when sky limited and by a factor of 10-16 when read noise limited), so the overall gain in sensitivity is between about 3 and 8. Below 2000 the data from the thermal vacuum testing are unclear. An Xe lamp at 1470 was used to get an absolute efficiency measurement with the camera compared to a standard diode. The result was a factor of 2 below the predicted curves presented in the WFPC2 handbook. However, the illumination pattern of the lamp was clearly not uniform, so the only secure conclusions are that WFPC2 does detect UV photons, but its throughput is uncertain at the 50% level. The camera throughput in the far UV was stable to at least 1% per day which is a considerable achievement, and shows that the extensive contamination control, material selection and bakeout procedures have been successful. Measurements of the lamp illumination pattern are ongoing, so more information may be available when they are complete. In the meantime, observers are advised to use a value for the efficiency of 75% of those in the handbook for F185W and below. Overhead times Because of changes in the ground system and the instrument (notably the lack of pre-flash), the phase II resource estimator has been revised. The changes make use of WFPC2 much more efficient. For WF/PC-1, the overhead time is 2.0 minutes per exposure + 6.3 mn per filter change. Ignoring a few special cases that we do only about 1% of the time, the overheads as actually implemented in TRANS and commanding the instrument are as follows: 1. The overhead per (non-parallel) exposure is 1 mn for readout + 1 mn only for exposure times greater than three minutes. On balance the exposure overhead charged has been kept at 2.0 mn, but with possible manual correction. CR split exposures are charged 4.0 mn of overhead. 2. Instrument setup: (filter changes) The overhead for a single filter is 1 mn. For two filters it is 2 mn. We use two filters only about 10% of the time, so the setup overhead is set as 1.1 mn (+ 3 mn for a spatial scan). 2. Acquisition overhead. There is a one mn tape recorder overhead at the end of each alignment, and a major frame synchronization overhead (two mn total) which have been absorbed into the 14 mn overhead associated with guide star acquisitions and into the 5.33 mn overhead associated with reacquisitions. This is under the generally true assumption that each acquisition has a separate alignment. Thus in the notation of the exposure time estimator, B should be 2.0 mn (or 4.0 mn for CR split), C should be 1.1 mn, Tgs should be 14 mn, and Treacq is 5.33 mn. CCD Performance The WFPC2 CCDs read noise gain and linearity have been measured in thermal vacuum in both signal chains. They are listed in the table below (courtesy James A. Westphal). Pipeline Enhancements When a WFPC2 exposure is short (<1 sec), shutter shading resulting from the finite time of flight of the shutter blade gives rise to uneven effective exposure time across the field of view. This effect has a worst case peak to peak amplitude of 4 % across a single chip in a 0.11 sec exposure, and it varies with the shutter blade in use to start the exposure. A very careful calibration of this was performed in thermal vacuum testing, primarily in order to allow the short exposure earth flats to be corrected. The effect is very stable and so a calibration correction has been implemented for it in the pileline. It is corrected by means of a multiplicative pixel correction that is applied after all other calibration steps are complete. The correction varies spatially according to a fixed reference file scaled for the appropriate exposure time. For large exposure times there is effectively no change in the result. The pipeline is now aware of the two possible gain states that WFPC2 uses. Different bias and dark corrections are applied depending on the gain and AREA mode. Chris Burrows CALIBRATION OF THE WF/PC NARROW BAND FILTERS USING THE ORION NEBULA We have calibrated the WF/PC narrow band filters Ha(F656N), [OIII](F502N), and [NII]658.8nm(F658N), using WFC images of the Orion nebula obtained on 13 and 14 August 1991. The initial set included a 200 sec exposure for the Ha(F656N) filter, a 300 sec exposure for [OIII](F502N), a 600 sec exposure for [NII]658.8nm(F658N), [OI]+[SIII](F631N), [SII](F673N), and a 10 sec exposure for the wide band F555W filter. Prior to calibration, all images have been mask corrected, A-to-D corrected, bias level corrected, bias corrected, preflash corrected, dark current corrected, and flat fielded using Space Telescope Science Data Analysis System tasks executed from within IRAF. Cosmic rays have been removed using IRAF tasks and by hand. Basically, the CCD sensitivity was determined by comparing the North quadrant (second frame, ODell et al. ApJ, June 1993) of the HST frames with the corresponding surface brightness determined from ground based Orion Nebula observations. Corrections for the continuum within each filter were made and it was necessary to correct the [NII] image for an Ha contribution. The ground based Orion Nebula images we used were from An Emission Line Survey of Galactic HII Regions (Hester et al. 1991, BAAS, 23, 1364). The level of continuum contamination was determined from the prelaunch characteristics for Effective Width of the filter EW, the transmission of the filter at the designated line Tline, and the ratio of emission line to continuum at the emission line Wline. Only three emission line filters (Ha, [OIII], and [NII]) could be properly calibrated. The continuum in each of these filters was no more than a few percent. In contrast, the large amount of continuum in the [SII], [OI]+[SIII] wideband F555W filters made it impossible to perform an accurate subtraction. Absolute calibration was done for the Ha filter. We found a calibration constant (effective area of the telescope system A times wavelength response of the telescope-camera-detector system sl times Tline) cHa = A sl Tline = 234 DNs photon-1 cm2. The flat-fielded images were normalized to compensate for the CCD chip-to-chip sensitivity difference. To this effect the North quadrant of the Orion images has been multiplied by factors of 1.038, 1.043 and 1.077 for Ha [NII], and [OIII], respectively, in the flat-fielding process. As a result, the absolute calibration constant (converting factor from pre-flat-field counts to absolute units) should have this flat-fielding factor removed from the calibration constant stated above. The wavelength-dependent relative sensitivities were determined by assuming that the line surface brightnesses in HST images were the average of the values of the three positions studied by Peimbert and Torres-Peimbert (1977), and Simpson (1973). Under that assumption, c[OIII]/cHa = 1.69, which is quite different from the predicted prelaunch value 0.69, and c[NII]/cHa = 1.05, which is also different from the predicted value 0.80. One possible explanation for the disagreement is that the reflectivity of the interference filters has decreased since launch, effectively broadening the filter transmission profile. According to my calculations, taking a 0.45% decrease of the reflectivity into account, c[OIII]/cHa becomes 1.37 instead of 0.69, and c[NII]/cHa = 0.99 instead of 0.80, which are in better agreement with the derived orbital values. This work was done using HST WF/PC team engineering observations and was analyzed under GTO contract NAG5-1626. Xihai Hu (Rice University Texas) HST DATA AND THE HST ARCHIVE The HST Archive was formally opened for archival research on 1 February 1993. Usage of the archive has increased steadily. For example, in June, 130 different astronomers (outside of those at ST ScI) logged in either as guest (stdatu.stsci.edu or stdata.stsci.edu; username guest; password archive) or as a registered user. (As described in the previous newsletter, registration (a simple process) is required to retrieve data from the archive.) These users retrieved approximately 4 GBytes of data from the archive. The archive hotseat (archive@stsci.edu or 410-338-4547) is responding to between 50 and 100 external inquiries a month. HST data are currently archived on a computer system known as the Data Management Facility (DMF). Although DMF has operated as the HST archive and although its capabilities have been expanded significantly over time, NASA never intended it to be the permanent archive. Instead, NASA entered into a contract with Loral AeroSys to build a permanent archive system, now known as ST-DADS, the Space Telescope Data Archive and Distribution System. When fully operational, DADS will have significantly more capability than DMF. For example, with DADS, ST ScI will be able to keep about five years of HST data online in optical jukeboxes compared to about half a year with DMF. The Loral portion of the DADS effort is now coming to an end and the transition from a developmental system to an operational archive is beginning. Loral has delivered the software designed to allow ST ScI to take data from DMF, populate the DADS catalog, and to archive data onto 6 Gbyte Sony optical disks. They expect to deliver a second set of software to support retrievals in late August. ST ScI took over the hardware maintenance of DADS in January and will formally take over responsibility for the maintenance and continued development of software for DADS in the early fall. Testing of the software in a realistic operational environment with real HST data is underway. Although this testing is revealing some problems, the number and severity of the problems appear to be consistent with those experienced in other systems of this complexity. None appears to fundamentally threaten our ability to switch to DADS. The highest priority goal of the software/operations team working on DADS is preparing the system for archiving data from the spacecraft and from DMF. The basic plan for the transition is as follows: We will continue to archive data to DMF until we are fully prepared to support archiving and retrieval from DADS. (DMF is currently being modified to accept data from WFPC2 and COSTAR.) About the time of the servicing mission, we expect to begin archiving data to DADS from the spacecraft and to transfer data from DMF to DADS. Following the transfer of most of the data from DMF to DADS, we will begin to encourage internal and then external users to switch to DADS. To facilitate the long-term archiving needs of the European Coordinating Facility and the Canadian Astronomical Data Center, we also make new Sony optical disks of the data for them during this period. Once we and NASA are confident that DADS fully duplicates the capability we have for external users and that users have had time to adjust to the new system, DMF will be retired from active service. If all goes well, the transition should be complete sometime next summer or fall. Users will begin to notice some changes in the HST archive in October or November as we begin to get ready to switch from DMF to DADS. The most obvious change will be that a new user interface, StarView, will become available on DMF. The first version of StarView will resemble the current user interface STARCAT in that it will be a CRT interface available on the archive host machines stdata and stdatu. (An X-windowed version of StarView is also under development, but will not be available until early 1994.) StarView has been developed at ST ScI and, ultimately, it will be the principal user interface to DADS at ST ScI. It has features that will make it easier to query all the fields in the DADS database as well as support the far more straightforward queries of most general users. When StarView becomes available on the archive host machines, users can expect new versions of the Archive Users Primer and Manual. As with all of the archive documentation, users will be able to obtain these manuals electronically from the docs directories on the host machines or on paper by request to the archive hotseat (or the User Support Branch). Knox Long AUTOMATIC E-MAIL NOTIFICATION OF UPCOMING HST OBSERVATIONS In order to notify observers of upcoming HST observations, we have instituted an automatic e-mail notification service. All observers with observations on the weekly timeline (which covers a three week period) will be sent an e-mail message which notifies them of this fact and contains a copy of the weekly timeline. Given the rather fluid nature of HST scheduling, the creation of the weekly timeline is the first point at which the schedule is reasonably definite (typically, 90% of the observations on the timeline will execute as scheduled). Observers with Real Time contacts will still be notified in advance by OSS. You may contact your USB TA if you have any questions about your observations. If you do not wish to receive the timeline, or would like to confirm your e-mail address, please contact usb@stsci.edu. Pete Reppert and Chris ODea HST USERS COMMITTEE REPORT MAY 1993 The committee met at ST ScI on May 27-28. We give below a summary of the resolutions and concerns in our report. A) All long-term prospects have become severely threatened by the budget being discussed from FY 1993/4 onward. There is every expectation that the full potential of the telescope will be realized in 1994 after the December 1993 refurbishment mission. Future instruments STIS and NICMOS, which are in mature stages of design and fabrication, will further enhance the telescope capability enormously. This large increase in scientific performance can only be realized with proper funding and operational support. In addition to instruments, the telescope requires an adequate program of flight replacement equipment. To decrease the HST budget NOW below the planned and necessary level during this time will certainly lose a large fraction of the scientific return, and place ALL of it at high risk. To the scientific community for whom this facility was built, such budget cuts seem unaccountable, and an enormous waste of the investment in this uniquely powerful observatory. We feel that the only sensible strategy to reach the full potential of HST is to maintain an adequate budget. B) The 1993/4 budget reductions place severe restrictions on the project immediately, at the very time when HST will recover its full capacity, and will require extra effort in commissioning, calibrating, and operating its new instruments. To apply severe budget cuts at this point is particularly poor timing, and will undoubtedly lead to a significant decrease in the amount of science done. Since the sole purpose of the mission is to do astronomical research, this must be kept as the top level goal of operations. We urge the project to apply cuts with this criterion in mind. We have made representations to NASAs Space Science Advisory Committee, NASA Headquarters, and to the Committee on Astronomy and Astrophysics of the National Academy of Sciences Space Studies Board, to express our deep concern. We have asked the AAS council to speak out on behalf of the astronomy community. We are convening a small conflict-free subcommittee of astronomers to become better acquainted with the HST budget, and to make any resulting suggestions or statements that seem appropriate. Other items 1. We commend the continued high efficiency of HST observing time, and are particularly impressed with plans that have the potential of making it better yet. We note that the ST ScI is also aware that scientific priorities and a dwindling high priority observation pool are factors in lowering the efficiency which are unavoidable. 2. We think that the cycle 4 proposal review should aim at approving a larger number of (scientifically excellent) proposals in view of a) the need to reach and service a larger section of the community; b) the expected decrease of exposure times without spherical abberation; and c) the increased efficiency of having a large observation pool. This will clearly pose an added burden on ST ScI, and we suggest that the phase II process be spread or split to ease this pressure. 3. We are very pleased at the excellent test results from WFPC2, and the encouraging news on the Solar Arrays and COSTAR. We support the SSWG efforts at maintaining scientific priorities in the plans for the refurbishment mission, and their particular attention to contamination dangers. 4. We stress the importance of having a person associated with new instruments at ST ScI, responsible for calibrations. We urge that plans for this be pursued for STIS and NICMOS. 5. We favorably received the report from the GHRS IDT about the near flawless operation of the GHRS since Side 1 was disabled in mid-1991 and look forward to the restoration of Side 1 operation. This is particularly important to the worldwide astronomy community a) for its unique echelle capability; b) as the far UV sensitivity greatly exceeds that of FOS; and c) as operation of IUE is threatened by both fiscal and technical pressures. We also suggest rearrangement of SMOV and cycle 4 activities for GHRS side 1 calibration and operation. 6. We are in agreement with the proposal to replace the film product machine with a new one, and to send laser printer output as the standard data product to observers. 7. We commend the actions and successful working of the FOS flat field working group. We will watch this type of issue in the future and may suggest formation of other such groups should the need arise. 8. We request at our next meeting that we be given a summary of the camera filters proposed for cycle 4, those approved, and the flat-field and calibrations plans that will be carried out as a consequence. 9. We suggest that ST ScI look into setting up a special e-mail account or phone number for logging calls from observers, and passing questions on to the appropriate people. The idea is to see whether this might be a labor-saving device for dealing with observer problems and inquiries. 10. We suggest that observers be asked to submit summaries of scientific results for inclusion in an annual (B.A.A.S.) report, as is done in many national observatories. 11. We are concerned about the apparent far UV scattered light in FOS spectra of red objects using the G190H and G130H gratings. We would like more information on this, if necessary from new calibration data, and some guidance for observers. 12. We have suggested to the AAS that they have invited talks on the HST scientific highlights and on the refurbishment mission, at the meeting in January 1994. 13. We discussed review processes. We are satisfied that the plans for cycle 4 time proposal review are fair. We are concerned that the process be viewed by the community as fair. We are concerned at the lateness of setting up the review panels for cycle 4, and suggest that for cycle 5, the review panels be set up much further ahead. 14. We were interested in the Gopher demonstration and regard it as a very useful tool for users. We also found the summary of the life-cycle of a proposal useful and suggest it be included in the acceptance letters to proposers, and published in the HST Newsletter. 15. We repeated our worry that the SMOV and ERO images released to the press not be seen as contradictory to the releases on image restoration to date. We urge that the images used be few and clearly show the image improvement and how new science is now possible. 16. We are pleased with the ST ScI response to our concerns about the difficulties in the scheduling of moving target programs. However, we are disappointed that the availability of Track 48 (which would help alleviate some of the scheduling problems as well) has been further delayed. 17. The distribution of GO support funds and the distribution of Hubble Fellows was reviewed. We are concerned that the community see this distribution as fair, and recommend sensitivity to this issue. 18. We suggest that the next version of RPSS be expanded to allow the observer to make tradeoffs where guide star availability is a problem. This will make the process easier on the ST ScI, and give the observer control over scientific tradeoff decisions. John Hutchings (chair), for the HST Users Committee POLICIES FOR PUBLICATION OF HST RESEARCH We wish to remind all authors again that research papers based on HST data must carry the following footnote: Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5- 26555. If the research was supported by a grant from ST ScI, the publication should also carry the following acknowledgement at the end of the text: Support for this work was provided by NASA through grant number from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronmy, Inc., under NASA contract NAS5-26555. So that your work can be included in official lists of HST research, please send two preprints of any research paper based on HST data to: Librarian ST ScI 3700 San Martin Drive Baltimore, MD 21218 USA Finally, please reference the relevant HST observing program identification number(s) in your papers, so that we can cross-index scientific papers with the original observing proposals. If you have questions regarding these instructions, please contact Sarah Stevens-Rayburn (410-338-4961; userid LIBRARY). Sarah Stevens-Rayburn SOFTWARE AND DATA ANALYSIS NEWS THE DATA PRODUCTS GUIDES In an effort to help GOs get started working with their HST data, the Science Data Analysts in the Research Support Branch and the Archive Scientists in the Data Systems Operations Branch have teamed up to produce a set of brief Data Products Guides. These Guides tell you how to read and understand the contents of your tape and how to display your data for a first look. They also provide additional information to help you understand the calibration process, recognize calibration errors in your data, and recalibrate your data with up-to-date reference files retrieved from the HST Archives. The Data Product Guides are now being distributed along with the GO data tape. To get a copy of these guides (there is one for each instrument), contact the User Support Branch (e-mail usb@stsci.edu, or phone 410-338-4413). You can also ftp PostScript versions of the guides from the documents directory of the archive host computers, stdata and stdatu, or from the observer/cookbooks directory on STEIS. A set of more extensive HST Data Handbooks are currently being developed, incorporating the information contained in these guides, along with more in depth information on the calibration, reduction, and analysis of HST data. The more detailed handbooks should be available in late 1993. Stefi Baum and Krista Rudloff STSDAS VERSION 1.3 RELEASE Version 1.3 of the Space Telescope Science Data Analysis Software (STSDAS) will be released by about the time this Newsletter is published. Off-site users may obtain STSDAS via anonymous ftp through the node stsci.edu, in the directory software/stsdas/v1.3. See the README file for retrieval and installation instructions. If you choose to get the software electronically (most sites do), please send us the electronic registration form even if you have already registered for an earlier release of STSDAS so that we may keep you up to date regarding revisions to the software and documentation. Users who do not have access to ftp may obtain the V1.3 release by writing to the STSDAS System Administrator (hotseat@stsci.edu), for a distribution tape and installation instructions. We expect to continue making major releases of STSDAS roughly every year and a half, but we also make the latest updates and bug fixes available to outside users in the form of incremental upgrades, or patch kits. These patches will be prepared as needed, probably every four to six months, and will also be available electronically. Concurrent with the STSDAS release, we have also released V1.3 of the TABLES external package. This package is intended for sites whose software requires the ttools and fitsio packages, but not the rest of STSDAS (e.g. SAOs XRAY package). The TABLES package now supports the short (16-bit) integer data type, and also includes the Interactive Graphics Interpreter (igi) task. As mentioned in the last Newsletter, STSDAS is now layered on TABLES, so it is necessary to install V1.3 of the TABLES package before installing V1.3 of STSDAS. In previous releases of STSDAS, the old versions of the calibration pipeline tasks for all the science instruments (i.e., the calXXX tasks) were distributed with the STSDAS source code and were collected in a separate external package called PIPELINE. That is, users saw the PIPELINE package listed in the top-level IRAF menu, along with STSDAS, NOAO, etc. With this release we have changed the name to HST_PIPELINE, and we are NOT including it in the STSDAS V1.3 distribution files. This package constituted a significant portion of the source code (and the resulting binaries) in STSDAS, and yet it was not often needed. Users who still want the older versions of the calibration pipelines will need to obtain and install the HST_PIPELINE external package separately. The latest version of the calibration routines can still be found in the individual instrument packages. We have also bundled the tasks in the vdisplay package into an external package. These tasks are specific to the VMS operating system, and were intended to support image display and analysis on the Gould-DeAnza display hardware. This machine has become obsolete in the age of workstations indeed, the Institute has only one such device left, and we suspect few other sites use them. It is therefore increasingly difficult to maintain the vdisplay software, and we anticipate withdrawing support for this package in the near future. Until then we will make the vdisplay package available as an add-on, external package. As with STSDAS, the TABLES, HST_PIPELINE, and VDISPLAY external packages are all available via anonymous ftp. New STSDAS Package Organization STSDAS V1.3 has been reorganized to make navigating the system much easier for users. The diagram on page 37 shows the new package structure. In essence, a new layer has been added to segregate the packages into broad categories: packages for calibrating HST data, packages for analysis or display of astronomical data, and general utilities. A few packages have been split up to emphasize the logical connection between some sets of tasks, and to keep the package menus small and informative. A new package, paradoxically called sobsolete, has been added for tasks that have been superseded by other utilities. All tasks in sobsolete will be retired by the V1.4 release, but placing them here permits users more time to find and use the new tasks. The shaded boxes in the diagram show which packages are implicitly loaded whenever the package above them is loaded. Thus, the fitsio tasks and the packages under the graphics, analysis, and toolbox packages are all automatically loaded after the user loads STSDAS; similarly, the ctools and synphot packages are implicitly loaded when the hst calib package is loaded. This approach means users have a useful set of utilities available at the outset of a session, without requiring them to type a whole bunch of package names before starting their analysis. This approach also minimizes the chance that users CL scripts will be unable to locate parameters for tasks that have been moved. More information about the package organization, including the diagram on this page, is available as a PostScript file on STEIS in the directory software/stsdas/v1.3/doc. New Tasks in STSDAS Several new tasks have appeared since the last incremental release of STSDAS (V1.2.3) in April 1993, and some of the highlights are given below. See the V1.3 release notes for complete details. Two new tasks have been added to the hst_calib.wfpc package to construct flat-field reference images from streak flat exposures. A new task has been added to the analysis.fourier package to convolve two images, and the performance of the lucy task in the analysis.restore package has been enhanced to make better use of available machine memory, rather than temporary disk files. A new task has been added to the hst_calib.synphot package, countrate, to make it easier to predict the response of the HST science instruments to user-specified astrophysical sources, which is extremely useful for preparing Phase I HST observing proposals. The fitsio tasks have been enhanced to accommodate the new FITS standard for image extensions. All FITS files that contain extensions, whether of type IMAGE, ascii TABLE, or binary BINTABLE can be read or written by the fitsio tasks. Generally, FITS extensions will be written to separate files on disk for subsequent access by standard IRAF/STSDAS tasks. Conversely, several images on disk can be combined into one FITS file for transport to another machine. Special rules apply to multi-group GEIS files that are written as FITS files with image extensions; please refer to the on-line help files for details. The imcalc task has been enhanced to automatically operate on all groups of a multi-group GEIS format image. Several other group friendly tasks are planned, and two of those tasks, gcopy and gstatistics are available now in the toolbox.imgtools package. Both of these tasks are modelled after similar tasks in the IRAF images package, and they will make the analysis of multi-group HST images and spectra considerably less tedious. One of the most frequently used IRAF utilities for spectral analysis is the noao.onedspec.splot task. But up until now it has been difficult to apply this task to spectra from FOS or HRS, in part because the dispersion solution for these data is stored in a separate file as tabulated wavelengths, rather than in the image header as coefficients of a function relating pixels to wavelengths. The new mkmultispec task in the hst_calib.ctools package solves that problem. It will derive the appropriate dispersion coefficients and store them in the *.c1h (flux) file in the (multispec) format that splot requires. Two other tasks in the hst_calib.ctools package, poffsets and specalign, have been added to align HST spectra that are shifted in wavelength relative to one another. These tasks are particularly useful for spectra obtained with the GHRS in FP-SPLIT mode. The calibration pipeline tasks have been relatively stable, as would be expected three and one-half years after launch. However, the new RSDP pipeline for the WFPC2 camera has already been written and testing with Thermal-Vac data is nearly complete. We expect the wfpc.calwp2 task to be included in a patch release of STSDAS in the fall of this year. The capability for reducing FOS polarimetry data has been a part of the FOS pipeline calibration (calfos) for some time. However, users often wish to examine or condition the spectra after the basic (i.e., wavelength and sensitivity) calibration, but before the polarimetric calibration proceeds. Or, they may wish to perform post-polarimetric calibration analysis. There are several new tasks in the hst_calib.fos.spec_polar package for this purpose, including specpol, polave, polbin, polnorm, and polplot. Please refer to the on-line help files for details. Users who would like more details about STSDAS software may wish to receive the STSDAS Newsletter which is prepared two or three times per year. The Newsletter provides many useful insights into using some of the more complicated tasks, advice on which STSDAS tasks are most appropriate for particular types of analyses, and descriptions of new tasks that are being developed. Please write to the STSDAS Group (hotseat@stsci.edu) to obtain the next issue. New/Updated Documentation Available With the release of STSDAS V1.3, our user manuals have been substantially revised and updated. These include the STSDAS Users Guide, the Synphot Users Guide, the STSDAS Installation Procedures/Site Managers Guide, and for local users and visitors, the ST ScI Site Guide for STSDAS and IRAF. Quick Reference Cards are also available for IRAF/STSDAS, CL programming, and site management. All of these documents are available from the STSDAS Group, and full sets will be mailed to sites from which we receive either a distribution request or an electronic registration form. Please note that these guides are also available in PostScript form in our ftp archive; the Quick guides are also included within the STSDAS source code, and can be found in sub-directories of stsdas$doc/user as PostScript files. Dick Shaw INSTITUTE NEWS BALTIMORE CHARTER RELEASED AT AAS MEETING At the AAS meeting in Berkeley last June, ST ScI announced the release of the Baltimore Charter for Women in Astronomy, a document intended to help increase the participation of women in the profession. The Baltimore Charter, included in full in this Newsletter, has four parts: 1) a statement of the fundamental assumptions behind the Charter, including that womens and mens abilities in science are equal and that astronomy in general will benefit from the increased participation of women; 2) a brief rationale for these assumptions; 3) a set of five recommendations by which astronomical institutions can increase the number of women; and 4) a call to action to all astronomers to become part of this effort. The five recommendations put forward in the Baltimore Charter address affirmative action, family issues, sexual harassment, gender-neutral language and illustrations, and physical safety. The Charter was presented in a poster session at the AAS meeting and was also released to the press at an AAS news conference, generating stories in the San Francisco Examiner, the Boston Globe, and a number of other papers around the country. The Charter grew from the September 1992 meeting on Women in Astronomy held at ST ScI, at which 18 working groups wrote reports on the topics of Scientific Excellence, Culture in the Workplace, Sociology of the Scientific Process, Quality of Life, Goals for Equal Representation, and Education. These reports were then distilled into a draft Charter by Sheila Tobias, noted science education activist and a participant in the conference. Subsequent drafts were generated by ST ScI astronomers Meg Urry, Laura Danly, and Ethan Schreier, with help from a number of other conference participants. The final Charter was circulated to the attendees of the 1992 Women in Astronomy conference, who were invited to be listed as authors in recognition of their initial contributions. The more than 160 who responded positively are listed as authors in the Proceedings of the Women in Astronomy conference. In order to make deep discussion of the issues more tractable, the Women in Astronomy meeting and hence the Baltimore Charter were focused very specifically on women in astronomy in the United States, at the graduate level and beyond. This represents our sphere of influence and our area of expertise. The Charter can, and we hope will, be generalized to other underrepresented groups, whose exclusion from science has a similar origin and often has been more complete. We also hope that the initiative represented by the Charter can be translated to other scientific disciplines. Future plans for the Charter include disseminating it widely within the astronomical community and collecting endorsements from professional institutions. Already the Board of Directors of the Association of Universities for Research in Astronomy (AURA), the parent organization of ST ScI and NOAO, has endorsed the Charter, and the President of AURA, Goetz Oertel, has sent a letter to the presidents of all 22 AURA institutions asking that they consider endorsing it as well. Early response has been very positive. In January, the AAS Executive Council will be asked to consider endorsing the Charter on behalf of the American Astronomical Society. Copies of the Charter are available in full-size posters, in TeX format via e-mail, or as part of the Proceedings of the Women in Astronomy conference. Please send requests for the Charter or the Proceedings to Shireen Gonzaga (userid gonzaga, 410-338- 4412). Meg Urry STEFI BAUM RECEIVES THE 1993 ANNIE JUMP CANNON AWARD The Annie Jump Cannon Award has been awarded this year to Stefi Baum, assistant astronomer at ST ScI, for her work on the kinematics of the ISM in Seyfert galaxies. She has used optical narrow band imaging and long slit spectroscopy, as well as radio continuum and spectral line synthesis imaging to study: (1) cold gas which is flowing into the nuclear regions and possibly fueling the central engine (monster) of the AGN and (2) warmer gas and cosmic rays which are flowing out from the nuclear regions in starburst or AGN driven superwinds. The Cannon Award is a research award offered annually by the American Association of University Women (AAUW), with advice from the AAS, to a woman for distinguished contributions to astronomy or for similar contributions in related sciences which have immediate application to astronomy. ANNUAL ST ScI MAY SYMPOSIA The annual 1993 ST ScI May Symposium on Extragalactic Background Radiation, A Meeting in Honor of Riccardo Giacconi, was held at the Institute on 1820 May, with over 100 participants. The meeting covered background radiation at all wavelength bands, from Gamma Rays to Radio. The invited speakers were: Jim Peebles (Introduction); Neil Gehrels (Gamma Rays); Gianni Zamorani and Rashid Sunyaev (X-Rays); Dick Henry and Peter Jakobsen (UV); Anthony Tyson and Simon White (Optical); Mike Hauser and Carol Lonsdale (IR); John Mather, Phil Lubin and Nicola Vittorio (Microwave); Malcolm Longair and John Peacock (Radio); and Martin Rees (Summary). Short contributions were presented in the form of posters. The proceedings will be published by Cambridge University Press. The topic for the ST ScI 1994 May Symposium is: The Analysis of Emission Lines, A Meeting in Honor of the 70th Birthdays of D.E. Osterbrock and M.J. Seaton. It is planned for 1618 May 1994. The deadline for registration is 1 April 1994. Inquiries and applications should be addressed to Barbara Jedrzejewski (410-338-4836; symposia@stsci.edu). Mario Livio WORKSHOPS A Workshop on Emission from QSO Absorption Line Systems was held at the Institute on 79 July 1993, with over 50 participants. The topics discussed included both line and continuum emission from absorption-line clouds. The invited speakers included: David Bowen, Ted Williams, Buell Jannuzi, Jacqueline Bergeron, Chuck Steidel, Brian Yanny, Esther Wu, Richard Ellis, Frank Briggs, Robert Brown, Stephane Charlot, Mike Fall, Alfonso Aragon, Mauro Giavalisco, Max Pettini, Palle Moller, Jill Bechtold and James Lowenthal. A Workshop on The ISM in Galactic Halos: Current Views, was held at the Institute on 1113 August 1993. The topics that were covered include: Molecules, IR and Dust; H I and Related Species; H II and Ionized Gas; High Energy Processes and various Theoretical Issues. About 70 participants attended the workshop. Mario Livio ST ScI MEETING ON HST CALIBRATION The ST ScI has started the planning for a meeting on HST Calibration to be held at the Institute from 1516 November 1993. This note describes the main aims of the Calibration Workshop and seeks to solicit interest in attending the meeting. An Image Restoration Workshop is being organized for later that week by Bob Hanisch (hanisch@stsci.edu). These have been scheduled back-to- back for the convenience of those wishing to participate in both meetings. In summary, the aims of the Calibration Workshop are: 1. to disseminate calibration results and techniques to the astronomical community in a forum open to both expert and novice, and 2. to establish and document the definitive instrumental calibration for HST data obtained prior to the servicing mission (i.e. pre-1994). The existing (pre-1994) HST archive contains a large body of unique science data obtained over three and one half years since the first astronomical observations were taken. The astronomical community has expressed growing interest in the archive data for research purposes and we anticipate that use of the archive will continue to develop in the years ahead. We have a responsibility to maintain the value of this important resource for science by making sure that the astronomical and instrumental calibrations are as good as possible. The initial calibration of the instruments was established by the Instrument Definition Teams (IDTs) during Science Verification in 1990 and has been maintained subsequently by staff at ST ScI. Inevitably, the performance of the instruments has changed during this long observing period and these changes have required frequent re-calibrations. Throughout this period of time, staff scientists at the Institute and the European Coordinating Facility (ECF) as well as members of the IDTs and General Observers have been analyzing HST data and wrestling with a variety of calibration problems. Hence, the main aim of the Workshop is to get all the various groups together to exchange information and then to go on to determine a definitive calibration for the first generation instruments. During the course of the meeting, we envisage forming small working groups of five to ten scientists per instrument to examine the detailed calibration of that instrument and to advise on specific instrument calibrations. We would hope to document results from the meeting as well as from the working groups. We are in the early planning stages for such a meeting and wish to hear from prospective attendees in order to gauge the level of interest. Please contact Chris Blades at ST ScI by way of e-mail (blades@stsci or scivax::blades) or letter within the next few weeks if you or a member of your research group would be interested in attending. If you are working on specific areas of instrument calibration and wish to present results, either through a verbal report or a poster, then let me know. At the ECF, Bob Fosbury (rfosbury@eso.org) is helping to organize the meeting and he is an alternative contact. Chris Blades ESA FELLOWSHIPS Astronomers of ESA member countries are reminded of the possibility of coming to do research at ST ScI as an ESA Fellow. Prospective fellowship candidates should aim to work with a particular member or members of the staff at ST ScI, and for this reason, applications must be accompanied by a supporting letter from ST ScI. Details of the fellowships and applications procedures can be obtained from the EDUCATION OFFICE,ESA,810 rue Mario Nikis, 75738 PARIS 15, FRANCE. A summary of the interests of the ESA staff members at ST ScI can be obtained from Dr. N. Panagia (panagia@stsci.edu or 6559::PANAGIA). Their interests and activities can best be assessed by reading the annual report of the Institute, the most recent of which is in BAAS, 25, 563, 1993. Completed application forms must be submitted through the appropriate national authority, and should reach ESA no later than 31 March for consideration in May, and no later than 30 September for consideration in November. A copy of the completed application should be send to the Chairman of the Postdoctoral Selection Committee (currently Michael Fall) at ST ScI. Selected Fellows must negotiate the commencement dates of their ESA Fellowships at ST ScI with the University Programs Division (c/o Nino Panagia) at least two months before their prospective starting dates. Nino Panagia HUBBLE POSTDOCTORAL FELLOWSHIP PROGRAM The Space Telescope Science Institute announces the continuation of the Hubble Fellowship Program in cooperation with astronomical institutions throughout the United States. The main objective of the program is to provide recent postdoctoral scientists of unusual promise and ability, opportunities for research on problems (largely of their own choosing) that are related to the Hubble Space Telescope (HST) science and are compatible with the interests of the Host Institutions. The Space Telescope Science Institute will conduct a worldwide competition to recommend and make awards to outstanding scientists at the recent postdoctoral level for carrying out HST-related research at participating United States institutions. A qualifying Host Institution must be a scientific, non-profit, United States organization where HST-related science can be successfully carried out. The program is open to scientists of any nationality who have earned their doctorates after 1 January 1991, in Astronomy, Physics, or related disciplines. The duration of the fellowship is a total of three years. The initial appointment is for one year and is renewable for two additional years. Funding for the second year will be awarded after a favorable review of the annual report, and funding for the third year is contingent upon a favorable mid-term review. Fellowships are awarded to individual postdoctoral scientists, and are administered through the Host Institutions. Contingent upon funding from NASA, up to 12 new Hubble Fellows will be appointed beginnning on or about September 1994. The detailed Announcement of Opportunity, including application instructions, is available upon request from: Hubble Fellowship Program Office Cheryl Schmidt - Ext. 4404 It may also be requested by e-mail to the following addresses: (BITNET): HFELLOWS%STSCI.EDU@INTERBIT.BITNET (INTERNET): HFELLOWS@STSCI.EDU (NSI/DECnet): 6559::HFELLOWS The application deadline is 19 November 1993. The new Hubble Fellow appointments are expected to begin on 1 September 1994. Minorities and women are strongly encouraged to apply. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for the National Aeronautics and Space Administration under Contract NAS5-26555. Applications received after 19 November 1993, may not be considered. The Hubble Fellowship Symposium for 1993 will be held at ST ScI on 25 and 26 October 1993. All those interested are welcome to attend. Colin Norman SABBATICAL AND LONG-TERM VISITORS AT ST ScI In order to promote exchange of ideas and collaborations in HST-related science, ST ScI expects to provide limited funds to support visiting scientists who wish to spend extended periods of time (typically three to six months) doing research at ST ScI. Typically the visitor is on sabbatical leave from his or her home institution. In general, these visitors will have the status of ST ScI employees and have access to the facilities available to staff members. Established scientists who might be interested in such a visit during the summer of 1994 or during the academic year commencing in September 1994 should send a letter specifying the suggested period for the visit and any other relevant details to the Visiting Scientist Program, c/o Andrew S. Wilson (e-mail awilson@stsci.edu) at ST ScI. Applicants should also include a statement of research plans and a copy of their curriculum vitae. The deadline for receipt of applications is 1 Feb 1994. Andrew Wilson GRADUATE STUDENT RESEARCH ASSISTANTSHIPS The Space Telescope Science Institute invites applications from advanced graduate students to pursue Ph. D. thesis-level research with members of the Institute staff. The scientific fields represented at the Institute cover much of modern astronomy, including theoretical, observational, and instrumental programs. Since ST ScI is not a degree-granting organization, all students must be enrolled in the graduate program at their home university. Applicants should have a batchelors degree, should have completed all required graduate course work and should have been admitted to the Ph. D. program at their home university, which must give permission for them to work at ST ScI. The program is intended for students who will spend at least one year at the Institute but proposals for shorter visits will also be considered. Applications from students at both U.S. and foreign institutions are invited. Applications for this program should be sent to the Personnel Manager, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, and should be clearly marked Graduate Student Program. They should include a curriculum vitae, a statement of research interests, and a letter from their advisor or departmental chairperson giving permission for them to work at ST ScI. Applicants should arrange for all their academic transcripts and three letters of recommendation to be sent directly to the Personnel Manager. The deadline for receipt of applications is 1 February 1994. EOE/AAE For further information, please contact Andrew S. Wilson at the Space Telescope Science Institute (e-mail awilson@stsci.edu). Andrew Wilson ELECTRONIC PICTURE BOOKS FOR READERS AND WRITERS What do Henry Ford and the ExInEd program of the Special Studies Office (SSO) at the Space Telescope Science Institute have in common? Both are pioneers in developing new vehicles to run on the superhighways of the future. For Henry, it was Model Ts; for the SSO, its a series of Electronic PictureBooks, which are learning aids being developed to share the highlights and challenges of space science research with todays modern adventure-seekers. ExInEds Electronic PictureBooks are part of a NASA-funded experiment to discover and develop new and better ways to assemble and distribute the results of astronomy and planetary science research, particularly images. Electronic PictureBooks run on Macintosh computers, and each contains a tutorial, text, color images, and many navigational features to assist the reader. For Readers. . . The growing list of Electronic PictureBook titles includes Gems of Hubble, which spotlights some of the most spectacular and informative images taken with the scientific instruments of the Hubble Space Telescope during its first year of operation; Magellan Highlights of Venus, a survey of the exciting first-year results of Magellan, the NASA spacecraft sent to map the surface of Venus with imaging radar; Terrestrial Impact Craters, a look at some of the most geologically interesting impact craters on Earth; Endeavour Views the Earth, a world tour by NASA Astronaut Jay Apt using shuttle pictures of the Earth; The World FactBook, a sourcebook designed to accompany Endeavour Views the Earth or to be used as a stand-alone reference work; Scientific Results from the Goddard High Resolution Spectrograph, an overview of the recent findings from one of the Hubble Space Telescopes five science instruments; and The Impact Catastrophe that Ended the Mesozoic Era, a collection of paintings by artist William Hartmann depicting the catastrophic event depicting the catastrophic event that is believed to have contributed to the demise of the dinosaurs. These Electronic PictureBooks and others are now available from SSOs electronic bulletin board at (410) 516-4880, on the commercial network America On-Line, and via the Internet with either anonymous ftp or retrieval software such as Gopher or Fetch to host address stsci.edu. For detailed instructions on how to download an Electronic PictureBook, please either write to us directly at Special Studies Office, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 or, if you have a fax machine, you can dial ExInEds FaxForum, an automated on-demand fax delivery system at (410) 516-4541. When calling the FaxForum, choose location number 3121 from the voice menu and then document number 301, and then simply follow the voice prompts to order the document delivered to your fax machine. . . . And Writers ExInEd is also accepting proposals for new Electronic PictureBooks from interested authors. Electronic PictureBooks are created from pre-existing text and graphics, usually in the form of slide sets, articles, or lecture material. If you are interested in having an Electronic PictureBook produced from your material, please contact us for authoring instructions, either by calling ExInEds FaxForum and choosing location number 3121 and then document number 302, or by writing to the Special Studies Office of the Space Telescope Science Institute at the address above. Happy motoring! Bob Brown RECENT STAFF CHANGES Carl Biagetti joined the Institute staff in March as Senior Technical Manager in SPD. Carl was previously a Supervisor at Loral AeroSys in Seabrook, MD. Roz Baxter transferred to Secretary in SPD/USB. Roger Bell, Fu-Zhen Cheng and Gopal Krishna have finished their appointments as Sabbatical Visitors in April and have returned to their home institutions, the University of Maryland, College Park, the University of Science and Technology, Hefei, China, and The Tata Institute of Fundamental Research, Pune, India, respectively. Bonnie Etkins joined the Institute staff in April as Secretary in SPD/SIB- SOB. Bonnie was most recently a Teacher at Great Beginnings Daycare in Havertown, PA. Andrea Ferrara, who has been an ESA Fellow in UPD for a year, left in July to resume his position at Arcetri Observatory, Florence, Italy. Claus Leitherer, Associate Astronomer in SPD/SPB, joined the AURA staff in June. Paola Pietrini left ST ScI in April, after a year spent as CNR Fellow in UPD, to resume her position at the University of Florence. Charles Proffitt, who was an AURA postdoctoral Fellow, has left ST ScI in May to become a resident astronomer at IUE Observatory, GSFC. Rita Sambruna, who is a graduate student at ISAS, Trieste, Italy, has joined the ST ScI Graduate Student Program, to work on X-ray properties of Blazars under the supervision of Meg Urry. Paola Sartoretti, who is a graduate student at University of Padova, Italy, has joined the ST ScI Graduate Student Program, to study the properties of the jovian satellite Io under the supervision of Melissa McGrath. Cheryl Schmidt has moved from the Directors Office to join UPD as Hubble Fellowship Program secretary. Mike Shara, coming back from a period of sabbatical leave at Columbia University, has joined the Science Program Selection Compartment of UPD. Peg Stanley was appointed to Chief, Observation Preparation Branch, in June. Anatoly Suchkov was a Visiting Astronomer in UPD before joining the regular staff in April as Planning Scientist/Assistant Scientist in SPD/SPB. Fang Zhou, who is a graduate student of New Mexico Tech, joined the ST ScI Graduate Student Program. He will work on radio galaxies and jets under the supervision of John Biretta. RECENT ST ScI PREPRINTS The following papers have appeared recently in the ST ScI Preprint Series. Copies may be requested from Sharon Toolan (410-338-4898, toolan@stsci.edu) at ST ScI. Please specify the preprint number when making a request. 714. Multiwavelength Monitoring of the BL LAC Object PKS 2155-304. I. The IUE Campaign, C.M. Urry, L. Maraschi, R. Edelson, A. Koratkar, J. Krolik, G. Madejski, E. Pian, G. Pike, G. Reichert, A. Treves, W. Wamsteker, R. Bohlin, J. Bregman, W. Brinkmann, L. Chiappetti, T. Courvoisier, A.V. Filippenko, H. Fink, I.M. George, Y. Kondo, P.G. Martin, H.R. Miller, P. OBrien, J.M. Shull, M. Sitko, A.E. Szymkowiak, G. Tagliaferri, S. Wagner, R. Warwick. 715. PG 0308+096 and PG 1026+002: Two New Short Period Binary Stars Resulting from Common-Envelope Evolution, R.A. Saffer, R.A. Wade, J. Liebert, R.F. Green, E.M. Sion, J. Bechtold, D. Foss, K. Kidder. 716. A Generalized Zeldovich Approximation to Gravitational Instability, M. Giavalisco, B. Mancinelli, P.J. Mancinelli, A. Yahil. 717. A Search for Intra-Night Optical Variability in Radio Quiet QSOs, Gopal- Krishna, R. Sagar, P.J. Wiita. 718. Optical CCD Imaging of GHZ-Peaked-Spectrum Radio Sources, C. Stanghellini, C.P. ODea, S.A. Baum, E. Laurikainen. 719. Color Gradients in Galaxies: Use of a Small Area Detector, W.B. Sparks, I. Jorgensen. 720. On the Mass of the Compact Object in the Black Hole Binary A0620-00, C.A. Haswell, E.L. Robinson, K. Horne, R.F. Stiening, T.M.C. Abbott. 721. The FK5 Extension on the FK4 System, M.G. Lattanzi, L.G. Taff. 722. Nova V2214 Ophiuchi 1988: A Magnetic Nova inside the Period Gap, R. Baptista, F.J. Jablonski, D. Cieslinski, J.E. Steiner. 723. What are the Mass-Loss Rates of O Stars? H. Lamers, C. Leitherer. 724. Galactic Superwinds, T.M. Heckman, M.D. Lehnert, L. Armus. 725. The Evolution of the Lithium Abundances of Solar-Type Stars. II. The Ursa Major Group, D.R. Soderblom, C. Pilachowski, S.B. Fedele, B.F. Jones. 726. The Soft X-ray Background and Galaxy Clusters, R. Burg, A. Cavaliere, N. Menci. 727. ROSAT Northern Cluster Surveys, R. Giacconi, R. Burg. 728. Titan: 1 to 5 mm Photometry, Spectrophotometry, and a Search for Variability, K.S. Noll, R.F. Fracke. 729. Cosmic-Ray Dominated Dense Molecular Gas in Normal and Starburst Galaxies, A. Suchkov, R.J. Allen, T.M. Heckman. 730. Soft X-ray Spectra of Seyfert 2 Galaxies, J.S. Mulchaey, E. Colbert, A.S. Wilson, R.F. Mushotzky, K.A. Weaver. 731. Detection of CO Emission from Massive Molecular Clouds in the Inner Disk of M31, R.J. Allen, J. Lequeux. 732. On the Location of the Oscillations in AE Aquarii, W.F. Welsh, K. Horne, R. Gomer. 733. QSO Heavy Element Absorption Line Systems and Large Galactic Halos by Satellite Accretion, B. Wang. 734. AGNs, Starbursts, and the Epoch of Galaxy Formation, T.M. Heckman. 735. Photometric and Spectroscopic Analysis of High Galactic Latitude Molecular Clouds. II. High Resolution Spectoscopic Observations of Na I, Ca II,Ca I, CH and CH+, B.E. Penprase. 736. Self-Absorbed Active Galactic Nuclei and the Cosmic X-Ray Background, P. Madau, G. Ghisellini, A.C. Fabian. 737. The Optical Structure of the Radio Galaxy Hercules A, A.C. Sadun, J.J.E. Hayes. 738. A New Way to Locate Corotation Resonances in Spiral Galaxies, B. Canzian. 739. Discovery of Double-Peaked Broad Line Emission from the Liner Nucleus of NGC 1097, T. Storchi-Bergmann, J.A. Baldwin, A.S. Wilson. 740. A Search for Rapid Variability in the Broad Ha Profiles of Seyfert and Radio Galaxies, M. Eracleous, J.P. Halpern. 741. Double-Peaked Emission Lines in Active Galactic Nuclei, M. Eracleous, J.P. Halpern. 742. Improving the Eclipse Mapping Method, R. Baptista, J.E. Steiner. 743. Unified Theories of Active Galactic Nuclei, C. M. Urry; Redshift Evolution of Damped Lyman Alpha Absorbers and the Epoch of Galaxy Formation, A.L. Kinney, R.L. White, R.H. Becker; High Spatial, Spectral, and Time Resolution Observations with the Hubble Space Telescope, A.L. Kinney. 744. The Dusty Emission Filaments of M87, W.B. Sparks, H.C. Ford, A.L. Kinney. 745. High Resolution Mid-Infrared Imaging and Astrometry of the Nucleus of the Seyfert Galaxy NGC 1068, J.A. Bratz, A.S. Wilson, D.Y. Gezari, F. Varosi, C.A. Beichman 746. Blue Stragglers: The Failure of Occams Razor? M. Livio. 747. On the Possibility of Obtaining Type Ia Supernovae and Accretion Induced Collapses from Cataclysmic Variables and Related Objects, M. Livio. 748. Multiwavelength Monitoring of Active Galactic Nuclei, C.M. Urry. 749. Ultraviolet Imaging Telescope: Globular Clusters in M31, R.C. Bohlin, E.W. Deutsch, K.A. McQuade, J.K. Hill, W.B. Landsman, R.W. OConnell, M.S. Roberts, A.M. Smith, T.P. Stecher. 750. The Mass-Luminosity Relation for Stars of Mass 1.0 to 0.08 Mo., T.J. Henry, D.W. McCarthy, Jr. 751. Restoration of FOC Imaging Data: Considerations when Choosing FOC PSFs, D.A. Baxter, P.E. Greenfield, W. Hack, A. Nota, R.I. Jedrzejewski, F. Paresce; Predicted Performance of the COSTAR-Corrected Faint Object Camera, R. Jedrzejewski, G.F. Hartig, A. Nota, P.E. Greenfield, D.A. Baxter, W. Hack, F. Paresce; In-Flight Performance of the Faint Object Camera of the Hubble Space Telescope: II, P. Greenfield, A. Nota, R. Jedrzejewski, W. Hack, H. Hasan, P. Hodge, D. Baxter, W. Baggett, F. Paresce. 752. Coronographic Imaging of the Bipolar Nebula around the Luminous Blue Variable R127, M. Clampin, A. Nota, D.A. Golimowski, C. Leitherer, S.T. Durrance. 753. A High Resolution Optical and Radio Study of Milky Way Halo Gas, C.E. Albert, J.C. Blades, D.C. Morton, F.J. Lockman, M. Proulx, L. Ferrarese. 754. The Evolution of the Lithium Abundances of Solar-Type Stars. III. The Pleiades, D.R. Soderblom, B.F. Jones, S. Balachandran, J.R. Stauffer, D.K. Duncan, S.B. Fedele, J.D. Hudon. 755. The Evolution of the Lithium Abundances of Solar-Type Stars. IV. Praesepe, D.R. Soderblom, S.B. Fedele, B.F. Jones, J.R. Stauffer, C.F. Prosser. 756. Intriguing Morphologies, Jets and Disks in Planetary Nebulae, M. Livio. 757. A Generalization of the Moving Mean, B. Bucciarelli, L.G. Taff, M.G. Lattanzi. 758. Dynamics of Conductive/Cooling Fronts: Cloud Implosion and Thermal Solitons, A. Ferrara, Yu. Shchekinov. 759. Hubble Space Telescope Imaging of the Narrow Line Region of NGC 4151, I.N. Evans, Z. Tsvetanov, G.A. Kriss, H.C. Ford, S. Caganoff, A.P. Koratkar. 760. The Proximity Effect and the Mean Intensity of Ionizing Radiation at Low Redshifts, V.P. Kulkarni, S.M. Fall. 761. Synthetic UV Lines of SiIV, CIV, and HeII from a Population of Massive Stars in Starburst Galaxies, C. Robert, C. Leitherer, T.M. Heckman. 762. The Population of Massive Stars in R136 from FOC Ultraviolet Observations, G. De Marchi, A. Nota, C. Leitherer, R. Ragazzoni, C. Barbieri. HOW TO CONTACT ST ScI Telephone: 410-338-4700 (reception); 410-338 + 4-digit extension of staff member Fax: 410-338-4767 Mail: ST ScI 3700 San Martin Drive Baltimore, MD 21218 USA E-mail: Most staff members at ST ScI can be reached on NSI/DECnet, Bitnet and Internet. Address formats are: NSI/DECnet: stscic::userid or 6559::userid BITNET: userid@stsci.bitnet Internet: userid@stsci.edu With few exceptions the userid is the staff members surname. Many are published in the Membership Directory of the American Astronomical Society. If you do not know the userid, please send the mail to the User Support Branch (userid USB), which will forward it. The USB is the central point of contact for scientists who wish to conduct research with HST. NEWSLETTER NOTES Comments on this issue of the ST ScI Newsletter should be addressed to the Editor, J. 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