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HST Observations of Saturnian Satellites during the 1995 Ring Plane Crossings
Nicholson, Philip D.; French, Richard G.; McGhee, Colleen A. +1 more
In May, August, and November 1995, Hubble Space Telescope (HST) observations during Saturn's ring-plane crossings allowed us to view saturnian satellites normally hidden to Earth-based observers in the glare of the rings. New measurements of Janus, Epimetheus, Prometheus, and Pandora have been combined to form revised orbital solutions using all t…
Hubble Space Telescope Observations of the Nucleus of Comet 9P/Tempel 1
Lamy, P. L.; A'Hearn, M. F.; Toth, I. +2 more
The nucleus of Comet 9P/Tempel 1, the target of the Deep Impact mission, was detected during Hubble Space Telescope observations taken with the wide-field planetary camera 2 (WFPC2) on 31 December 1997 when the comet's solar phase angle was 3.°8, its heliocentric distance was 4.48 AU, and its geocentric distance was 3.53 AU. Sixteen images were ta…
Coordinated 1996 HST and IRTF Imaging of Neptune and Triton. II. Implications of Disk-Integrated Photometry
Baines, K. H.; Sromovsky, L. A.; Fry, P. M. +1 more
Near-IR groundbased observations coordinated with Wide Field Planetary Camera 2 (WFPC2) HST observations (Sromovsky et al.Icarus149, 416-434, 459-488) provide new insights into the variations of Neptune and Triton over a variety of time scales. From 1996 WFPC2 imaging we find that a broad circumpolar nonaxisymmetric dark band dominates Neptune's l…
Water Production of Comets 2P/Encke and 81P/Wild 2 Derived from SWAN Observations during the 1997 Apparition
Schmidt, W.; Bertaux, J. -L.; Lallement, R. +5 more
The water production rates of comets 2P/Encke and 81P/Wild 2 during their 1997 apparitions have been estimated from Lyman-α observations of the SWAN instrument and compared to previously published values. 2P/Encke was detected 28 times from few days preperihelion to 1.4 AU postperihelion with a perihelion water production rate QH 2…
Uranus' Apparent Seasonal Variability in 25 HST Filters
Karkoschka, Erich
Hubble Space Telescope (HST) images of Uranus taken in 1997 reveal that Voyager's view of the southern hemisphere was not representative of the rest of the planet. The banded structure with hemispherical asymmetry, presented in 25 filters between 0.27 and 2.03 µm wavelength, caused Uranus' full disk to darken by as much as 35% between 1985 a…
NOTE: HST/FGS Observations of the Asteroid (216) Kleopatra
Lattanzi, M. G.; Tanga, P.; Berthier, J. +4 more
Interferometric observations of asteroid (216) Kleopatra were performed in January 2000 using the Fine Guidance Sensors (FGS) aboard HST. The FGS data obtained clearly suggest that (216) Kleopatra is composed of two lobes in contact, in agreement with the radar data (Ostro et al. 2000, Science288, 836-839), and provide more precise constraints on …
An HST Study of Jovian Chromophores
Simon-Miller, Amy A.; Gierasch, Peter J.; Banfield, Don
A principal components analysis was performed on Hubble Space Telescope WFPC2 images of Jupiter from October 1995 and October 1996. Global maps in the F410M, F555W, F673N, and F953N filters were analyzed. These are continuum wavelengths in Jupiter's spectrum, sensitive to reflection from the visible cloud deck. The primary principal components cor…
Coordinated 1996 HST and IRTF Imaging of Neptune and Triton. I. Observations, Navigation, and Differential Deconvolution
Baines, K. H.; Sromovsky, L. A.; Fry, P. M. +3 more
On 13-14 August 1996, we carried out the first coordinated contemporaneous imaging of Neptune, using the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 and the NASA Infrared Telescope Facility (IRTF) NSFCAM InSb camera to obtain high spatial resolution absolutely calibrated imagery at wavelengths from 0.2 to 2.5 µm. We used nine …
Middle Ultraviolet Spectroscopy of Pluto and Charon
Krasnopolsky, Vladimir A.
The first Pluto's spectrum in the range 2000 to 2500 Å has been extracted from the Hubble Space Telescope (HST) archive observations acquired during 24 orbits. Although the spectral intensity is very weak and smaller than that for Titan by a factor of 100, the spectrum has a signal-to-noise ratio of 10-15 at the resolution of 10 Å. The mean geomet…
Photometric Modeling of the Epsilon Ring of Uranus and Its Spacing of Particles
Karkoschka, Erich
The ring model of Irvine (1966, J. Geophys. Res.71, 2931-2937) is used to explain the longitudinal brightness variation of the ɛ ring of Uranus observed by Voyager 2 and with the Hubble Space Telescope, while basic ring properties are based on occultation data. The observations span a factor of 600 in the range of phase angles (0.03-20°) which all…