GEOMETER Update
• Get new version of GEOMETER from Team web
site after August 8.
• Some new parameters now computed (illum
angles for “near point” of non-intersecting lines of
sight); bug fixes which affect occultations at high
precision (aberration, double precision).
• Uses NAIF “ICY” package available from
naif.jpl.nasa.gov via ftp.
• User must ensure all appropriate kernels are
loaded (kernels available from secure Cassini
web site
https://cassini.jpl.nasa.gov/csos/io/spice).
• Requires IDL 6.1.
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UVIS Team Meeting
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Capabilities
• Calculate all relevant geometric parameters
for corners and centers of all pixels and
FOVs.
• GEOMETER_ENGINE may be called
separately by user-supplied software: returns
pointing for one pixel at one time.
• Visualization routines for mapping in sky,
target body, and ring coordinate systems.
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SkyMap Pre-SOI
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Target View Pre-SOI
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Target View High Inclination
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List of Planned Upgrades
• Lat/Lon grid on target bodies.
• Shading of unlit hemisphere and shadowed
rings.
• Plotting of FOV footprints at multiple times to
allow for user control of how FOVs are
displayed.
• Performance may be improved by using new
vectorized ICY routines, (but backwardscompatability issues).
• Let me know if you have suggestions or
needs for new features in GEOMETER.
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UVIS Team Meeting
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UVIS Ring Observations
• Stellar and solar occultations.
• FUV and EUV spectra.
• Meteoroid impact detection searches.
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UVIS Team Meeting
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Stellar Occultations
• Initial set of 7 occultations completed. Next
occ on July 25, 2006.
• Range of resolutions and signal strengths.
• Each part of ring system sampled at least
once; parts of A ring sampled 9 times.
• Optical depth variations observed in A ring.
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UVIS Team Meeting
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Xi Ceti Rev 00A Bin=125
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Ring Occultation Paths
F
A ring
B ring
C ring
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26 Tau Rev 8 Bin = 500
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Alp Vir Ingress Rev 008 Bin = 50
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Alp Vir Egress Rev 008 Bin = 50
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Del Aqr Rev 008 Bin = 250 (1 second)
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UVIS Team Meeting
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Alpha Leo Rev 009 Ingress and Egress Bin = 50
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26 Tau Rev 010 Bin = 500
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Sig Sgr Rev 011
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Gravitational Wake Geometry
to star

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Janus 2:1 Density Wave
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Encke Gap
Pan Wakes
Density Waves
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Zero Phase FUV Image
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26 Tau Rev 008 FUV Image
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26 Tau Rev 008 EUV Image
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Rev 00A Impact
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Rev 007 Impact
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Rev 011 Impact
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Status
• Nearing end of first inclined orbit series: time
to analyze data in more detail.
• Opacity variations reveal 3D structure of
rings.
• Density waves provide mass and ring height
measurements.
• No strong impact signals: end of this series
will allow constraints to be placed on flux.
• Radial fluctuations in FUV albedo show
uneven distribution of non-icy contaminants.
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