Mission Information
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MISSION_NAME |
GROUND BASED ATMOSPHERIC OBSERVATIONS
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MISSION_ALIAS |
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MISSION_START_DATE |
1993-01-01T12:00:00.000Z
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MISSION_STOP_DATE |
1995-01-01T12:00:00.000Z
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MISSION_DESCRIPTION |
Mission Overview
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From [KARKOSCHKA1994]
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Full-disk albedo spectra of the jovian planets and Titan were
derived from observations at the European Southern
Observatory in July 1993. The spectra extend from 300- to
1000-nm wavelength at 1-nm resolution. The signal-to-noise
ratio is approximately 1000 in the visible. The accuracy is
2 percent for relative and 4 percent for absolute albedos.
Colors and magnitudes were also determined. Some 40-60 Raman
scattering features are visible in the spectrum of each
jovian planet. A Raman scattering model with five parameters
adjusted for each planet can explain these features. A
methane absorption spectrum is given which fits methane
features in the spectra of the jovian planets and Titan. It
differs from room-temperature laboratory spectra but it is
consistent with some limited laboratory data at cold
temperatures. Three new, weak methane bands were detected in
the spectra of Uranus and Neptune. A strong absorption band
in Jupiter's spectrum is possibly due to water, confirming a
strong depletion of oxygen in the probed part of Jupiter's
atmosphere.
From [KARKOSCHKA1998]
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Full-disk albedo spectra of the jovian planets and Titan were
derived from observations at the European Southern
Observatory in July 1995. The spectra extend from 300 to
1050 nm wavelength. The spectral resolution is 0.4 nm
between 520 and 995 nm, and 1 nm elsewhere. The accuracy of
the albedo calibration is 4 percent. UBV magnitudes were
also determined. Raman scattering was quantified for each
planet. Methane and ammonia bands are shown at 0.4 nm
spectral resolution, including a new band at 930 nm
wavelength which is probably due to ammonia. Maps of the
variation of these absorptions across the disks of Jupiter
and Saturn are displayed. Saturn's spectrum is undisturbed
by light from its rings due to the edge-on geometry during
the observations. The albedo of Uranus near 1 micro-m
wavelength has dropped almost 10 percent between 1993 and
1995, while there has been no change in the ultraviolet. The
signature of light from Titan's surface yielded a path length
of 4 km-am of methane in Titan's atmosphere. The temperature
dependence of the width of the 890-nm methane band was used
to measure temperature variations at three altitude levels,
resulting in the first temperature maps of Jupiter and Saturn
based on reflected sunlight. Jupiter displays a banded
temperature structure with some discrete features of a few
Kelvin amplitude. Saturn's north-south temperature asymmetry
has reversed since the Voyager observations.
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MISSION_OBJECTIVES_SUMMARY |
UNK
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REFERENCE_DESCRIPTION |
Karkoschka, E., Spectrophotometry of the Jovian Planets and Titan at 300-
to 1000-nm Wavelength: the Methane Spectrum, Icarus, 111, 174-192, 1994.
Karkoschka, E., Methane, Ammonia, and Temperature Measurements of the
Jovian Planets and Titan from CCD-Spectrophotometry, Icarus, 133, 134-146,
1998.
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