HUBBLE SPACE TELESCOPE DAILY REPORT # 3173 PERIOD COVERED: DOY 218 OBSERVATIONS SCHEDULED (see HSTARS below for possible observation problems) NICMOS 8790 NICMOS Post-SAA calibration - CR Persistence Part 1. A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. STIS/CCD 8902 Dark Monitor-Part 2. The Space Telescope Imaging Spectrograph (CCD) was used to monitor the darks. STIS/CCD 8904 Bias Monitor-Part 2. The Space Telescope Imaging Spectrograph (CCD) was used to monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4 in order to build up high-S/N superbiases and track the evolution of hot columns. STIS/MA1/MA2 8920 Cycle 10 MAMA Dark Measurements. the MAMA detector dark noise, and is the primary means of checking on health of the MAMA detectors systems through frequent monitoring of the background count rate. WFPC2 8934 WFPC2 Decontaminations and Associated Observations Pt. 3/3 This proposal is for the monthly WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check. WFPC2 8938 WFPC2 CYCLE 9 SUPPLEMENTAL DARKS pt3/3. This dark calibration program obtains 3 dark frames every day to provide data for monitoring and characterizing the evolution of hot pixels. STIS/CCD 9317 Pure Parallel Imaging Program: Cycle 10. The Space Telescope Imaging Spectrograph (CCD) was used to perform the default archival pure parallel program for STIS during cycle 10. GO 9344 The Asymmetric Atmosphere of Uranus We propose to image Uranus as the planet plunges toward equinox in 2007. Recent HST images during this unique epoch {6818: Hammel, Lockwood, and Rages; 7429: Tomasko and Karkoschka; 7885: Hammel, Karkoschka, and Marley} have revealed: {i} strongly wavelength-dependent latitudinal structure, {ii} the presence of numerous visible-wavelength cloud features in the northern hemisphere, {iii} zonal winds which may deviate from the smooth profile implied by the Voyager observations in 1986, and, {iv} in the near-IR, discrete features northward of +25 degs that have the highest contrast ever seen for a Uranian cloud {Karkoschka 1998, Science 393, 765-767; Hammel et al. 2001, Icarus 153, 229-235}. Specific scientific issues we will address with new observations are: whether the northern features are indicative of intrinsic change or result simply from a change of viewing angle; the shape and stability of the zonal wind profile; and the source of the as-yet unexplained variations of the atmospheric reflectivity. When possible, observations will be coordinated with ground-based imaging, spectroscopy, and photometry. This period approaching equinox is the first opportunity {in the era of modern instrumentation} to examine the far regions of the northern hemisphere on Uranus. NICMOS 9360 Paschen-alpha Imaging of a SIRTF-Selected Nearby Galaxy Sample We propose to carry out a NICMOS snapshot survey in the Paschen-alpha {PAlpha} emission line and H-band of the sample of galaxies being observed at 3.5 -- 160 microns as part of SIRTF Nearby Galaxies Survey {SINGS} and a related guaranteed time survey of starburst galaxies. The PAlpha images, accessible only from HST, will be combined with groundbased HAlpha imaging to measure the extinction in the star-forming centers of these galaxies, and obtain robust, extinction- corrected maps of the massive star formation rate {SFR}. The PAlpha data by themselves will provide reliable `extinction- free' SFRs, and a cross-calibration of the {dust--affected} HAlpha-- and UV--based SFRs. The PAlpha--based SFR measurements will extend the SFR-vs.-gas density law {Schmidt--law} to surface densities at least 30 times higher than what is accessible using HAlpha--based SFR measurements alone, bridging the gap between normal galaxies and IR--luminous starbursts. Furthermore, the combination of the HST PAlpha images with the SIRTF images and spectra, as well as ancillary ground--based UBVRIJHK images and GALEX UV images being obtained as part of the SINGS project, will provide a definitive study of the radiative transfer of starlight and dust heating in star--forming galaxies. The processed NICMOS images will be incorporated into the public SINGS Legacy Data Archive, to enable scores of follow-up studies by the astronomical community at large. NICMOS 9386 Infrared Photometry of a Statistically Significant Sample of KBOs While the discovery rate of Kuiper Belt objects is accelerating, the physical study of this new region of the solar system has been slowed by a lack of basic astrophysical data. Photometric observations of the majority of the more than 400 known KBOs and Centaurs are rudimentary and incomplete, particularly in the infrared. The multicolor optical-infrared photometry that exists for a small subset of KBOs often shows significant discrepancies between observations by different observers. Their intrinsic faintness puts them at the practical limits of ground-based systems. In July 2001 we began what will be the largest uniform sample of optical photometry of KBOs with a WFPC2 SNAPSHOT program that will perform accurate photometry at V, R, and I on a sample of up to 150 targets. We seek to greatly enhance the value of this survey by obtaining J and H photometry on the same sample using NICMOS. Combined optical and infrared broad band photometry is a far more powerful tool for physical studies than is either alone. Our sample includes objects that will be observed at thermal infrared wavelengths by SIRTF and will be used with those data to derive the first accurate diameters, albedos, and surface properties for a large sample of KBOs. ACS 9425 The Great Observatories Origins Deep Survey: Imaging with ACS We propose a Treasury program of ACS imaging as part of the Great Observatories Origins Deep Survey {GOODS}, covering 320{square}', or 32* the area of the two original WFPC2 HDFs, to within 0.5--0.8 mag of their depth in four ACS bands, BViz. The two GOODS fields, the Hubble Deep Field North and Chandra Deep Field South, are the premier deep survey areas from X-- ray to radio wavelengths. ACS data will provide unique angular resolution, sensitivity, and wavelength coverage to close the gap between the deepest Chandra and SIRTF observations. Supported by extensive imaging and spectroscopy from the VLT, Keck, Subaru, NOAO, Gemini, VLA, JCMT, and other facilities, the combined GOODS data set will make it possible to map the evolution of the Hubble sequence with redshift, reconstruct the history of galaxy mass assembly, star formation and nuclear activity from the epoch of reionization to the present, trace the growth of density perturbations via cosmic shear, and, with properly phased z--band observations, detect ~ 12 Type Ia supernovae at 1.2