HUBBLE SPACE TELESCOPE DAILY REPORT #1884 PERIOD COVERED: 0000Z (UTC) 05/22/97 - 0000Z (UTC) 05/23/97 Daily Status Report as of 143/0000Z 1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED: 1.1 Completed Two Sets of STIS/CCD 7076 (STIS Corrector Alignment, Fine) The Space Telescope Imaging Spectrograph was used to make observations of BPM16274 as part of a fine correction alignment and calibration procedure. This is to refine the STIS corrector system into alignment so that the image quality at the spectrographs slit plane is optimized. The observations were executed as scheduled, and no anomalies were noted. 1.2 Completed WF/PC-2 6355 (A UV Atlas of Nearby Galaxies) The WF/PC-2 was used to make ultraviolet observations of the nearby galaxy IC4710. The aim of the project is to build a reference ultraviolet atlas of galaxies whose optical images are well known, with the highest possible degree of information, covering all the morphological types and luminosity classes. The observations were executed as scheduled, and no anomalies were noted. 1.3 Completed WF/PC-2 7553 (Pure Parallel Archive Survey II) WF/PC-2 parallel observations were obtained in the ultraviolet in search for interesting objects. This program is designed to find extragalactic sources with near ultraviolet excesses (3000 A0) outside the galactic plane and far ultraviolet sources (1600 A0) in the galactic plane. The procedure was executed as scheduled, and no anomalies were reported. 1.4 Completed WF/PC-2 6902 (WF/PC-2 Cycle 6 Photometric Calibration Monitor UV/OPT STD) The WF/PC-2 was used to make both ultraviolet and optical photometric observations of the standard star GRW+70D582 as part of a Cycle 6 calibration procedure. This observations was done immediately before and after decontamination procedures. The observations were completed as planned, and no problems were reported. 1.5 Completed WF/PC-2 7588 (Measuring Q0 With Type IA Supernovae) The WF/PC-2 was used to make observations of supernova SN1997A2 in order to measure the Q0 parameter. This is in order to produce a precise Hubble diagram which can be used to measure the cosmic deceleration and global curvature of the universe. HST can make an essential contribution by providing photometry with substantially higher precision and better temporal coverage than can be obtained from the ground. The observations were executed as scheduled, and no anomalies were noted. 1.6 Completed NIC/2/3 7048 (NICMOS Parallel Thermal Background Test) The Near Infrared Cameras (Cameras One, Two and Three) were used to make observations of an object designated as Target-1 in order execute measurements of the stability of the HST thermal emissions. The observations were executed as scheduled, and no problems were reported. 1.7 Completed WF/PC-2 6853 (Emission Features Near Eclipsed Io) The WF/PC-2 was used to make observations of Jupiter's moon Io during an eclipse of the moon. The high spatial resolution of the WF/PC-2 will allow an extension of the ground based observations of interactions between Io and the Jovian plasma torus. The observations were completed as scheduled, and no anomalies were reported. 1.8 Completed FGS 6566 (Calibrating the Mass-Luminosity Relation at the End of the Main Sequence) The FGSs were used to make astrometric observations of the components of the low-mass, binary system, star GJ1215 in order to make a calibrations of the mass-luminosity relation at the end of the main sequence. The individual stars have masses of less than 0.2 solar masses. The observations were completed as scheduled, and no problems were noted. 1.9 Completed WF/PC-2 6565 (Imaging of Proto-Planetary Nebulae) The WF/PC-2 was used to make high resolution observations of the proto-planeatary nebula IRAS17441 which is known to show bipolar morphologies in ground-based observations. The observations were executed as scheduled, and no anomalies were noted. 1.10 Completed NIC/1 7152 (NICMOS Absolute Photometry Test) The Near Infrared Camera (Camera One) was used to conduct an absolute photometric calibration testby making observations of object P330E. A dark calibration image was also taken. The observations were completed as scheduled, and no anomalies were reported. 1.11 Completed WF/PC-2 7029 (WF/PC-2 Cycle 6/SMOV Lyman Alpha Check-Part 2) The WF/PC-2 was used to make observations of the WD0310-688 in order to obtain far-ultraviolet (Lyman Alpha) measures of the system's throughput. This is to quantify any contamination of the WF/PC-2 pick-off mirror caused by SMOV activities. The observations were completed as planned, and no anomalies were reported. 2.0 FLIGHT OPERATIONS SUMMARY: 2.1 Guide Star Acquisitions: Scheduled Acquisitions : 11 Successful : 11 Scheduled Reacquisitions : 5 Successful : 5 2.2 FHST Updates: Scheduled : 22 Successful : 22 2.3 Operations Notes: Due to the experience with the MAMA2 during the high voltage ramp-up on day 142, there was concern that the event count rate on the day 143 ramp-up could trip operational limits (the yellow limit is 4000; the red, 5000 -- on day 142 there were two instances of just over 4000 counts). Accordingly, at STScI request, an operations procedure was developed to bypass the SMS high voltage commanding and to use real-time PSTOL procedures to turn on the MAMA2 high voltage. The new procedure worked well, although it was observed that the event counts never exceeded the operational limits, and the SMS commanding would have succeeded. Since it has been observed that the event counts have generally been decreasing with each orbit turn on, a decision will be made today whether to continue with the precautionary real-time commanding or to allow the SMS commanding to occur. An SSR interrupt log dump was performed at 143/0121Z. 3.0 SIGNIFICANT FORTHCOMING EVENTS: Continuation of normal science and SMOV operations. /DMH