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The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report spectra(More)
Titan's optical limb from Voyager 1 images, although no wavelength dependence was investigated. Using a high We measured the location, size, and shape of Titan's shadow in five images taken with the Hubble Space Telescope in 1995. phase-angle image in the clear filter (480 nm) from Voyager We inferred the altitude of Titan's optical limb at wavelengths 2,(More)
Tomasko and Smith (1982). Examination of the Voyager 2 (V2) data in Smith et al. (1982) reported no significant New measurements of Titan's hemispheric brightness asym-variation from V1 to V2, consistent with a seasonally vary-metry from HST images from 260 to 1040 nm show that the contrast is strongest near 450 nm (blue) and, with the opposite ing(More)
Near-infrared images of Uranus taken with the Hubble Space Telescope in July and October 1997 revealed discrete clouds with contrasts exceeding 10 times the highest contrast observed before with other techniques. At visible wavelengths, these 10 clouds had lower contrasts than clouds seen by Voyager 2 in 1986. Uranus' rotational rates for southern latitudes(More)
The atmospheres of the gas giant planets (Jupiter and Saturn) contain jets that dominate the circulation at visible levels. The power source for these jets (solar radiation, internal heat, or both) and their vertical structure below the upper cloud are major open questions in the atmospheric circulation and meteorology of giant planets. Several observations(More)
The aftermath of the impacts of periodic comet Shoemaker-Levy 9 on Jupiter was studied with the Wide Field Planetary Camera 2 on the Hubble Space Telescope. The impact debris particles may owe their dark brown color to organic material rich in sulfur and nitrogen. The total volume of aerosol 1 day after the last impact is equal to the volume of a sphere of(More)
Es wird eine Methode beschrieben die es ermöglicht, mit relativ geringem numerischen Aufwand Ausnahmen zur Rosserschen Regel für die Riemannsche Zetafunktion zu finden. Vor kurzem von R. P. Brent durchgeführte systematische Rechnungen zeigen, daß durch unsere Methode im gemeinsam untersuchten Bereich alle Ausnahmen erfaßt werden. We describe a method which(More)
The transmission of the filter FQCH4N-D varies by 20 percent across the filter while the mean wavelength shifts by 3 nm. For objects with a flat spectrum across the main bandpass (889–897 nm), the flatfielding removes the spatial variations except for the outer corner, for which we give the necessary photometric correction. On the other hand, for objects(More)
We examine the noise contributed by the WFPC2 flatfields during normal calibration, and provide new low-noise flats for 41 filters. Highly exposed science images (>20,000 electrons per pixel) will show significant noise reduction if these new flats are used; this is especially true for images on the PC1 chip. For some ultraviolet filters a significant(More)
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