CIRS Ring Observations: Submm, Temp and Stellar Occultations Linda Spilker, Scott Edgington, Rich Achterberg, Stuart Pilorz, Shawn Brooks April 26, 2004

26 April 2004LJS-2 Key Observing Parameters Observe inside 25 R S to resolve rings with FP1 Observe rings over range of: –Solar Elevation angle (20°, 13°, 7°) –Spacecraft Elevation Angle (±10°, ±25°, ±40°, ±60°, e.g. lit and unlit face) –Local hour angle (across shadow boundaries) –Phase Angle (High and Low)

26 April 2004LJS-3 Key Ring Observing Periods Saturn Orbit Insertion –Highest resolution possible in entire mission Early Orbits (A, B) Occultation Orbits (6-14) Titan 180 upleg (26-38) Titan 180 downleg (39-46) High Inclination Sequence (52-74)

26 April 2004LJS

26 April 2004LJS-5

26 April 2004LJS-6

26 April 2004LJS-7

26 April 2004LJS-8 Submm Summary 80 observations in timeline No high phase observations (lit or unlit) after Rev 44 Lit Rings: –Only 3 lit ring observations above 40 deg inclination –Very few observations on 180 downleg Unlit Rings –Very few low phase observations until end of mission Some inclination and phase coverage might be filled in with long, slow UVIS stellar occultations (not optimal since local time will vary throughout occultation)

26 April 2004LJS-9 *Need to adjust deep space positions on some obs. in Revs 6- 14, too far away

26 April 2004LJS-10

26 April 2004LJS-11 Temp Summary 70 observations in timeline Temp measurements also possible with Submm scans No high phase observations (lit or unlit) after Rev 44 Lit Rings: –Only 6 lit ring observations above 40 deg inclination –Very few observations on 180 downleg Unlit Rings –Very few low phase observations until end of mission Some coverage might be filled in with VIMS Latphase observations and ISS radial scans (limited coverage of rings, usually only a few points per ring)

26 April 2004LJS-12 Stellar Occultations by Rings Three CW Leo occultations in tour Rev 26, 31, 70, 71 –Only one occultation (Rev 26) of A, B and C rings Other occultations possible in Revs One Eta Carinae occultation– Rev 70

26 April 2004LJS-13 Rev 26 CW Leo

26 April 2004LJS-14 Rev 31 CW Leo

26 April 2004LJS-15 END

26 April 2004LJS-16 Backup Material

26 April 2004LJS-17 Submm Observations in Tour KEY 39 SL59MP 39 = Rev # L = Lit U = Unlit 59 = S/C inclination MP = mid-phase Red = Early Green = upleg Blue = downleg

26 April 2004LJS-18 Temp Observations in Tour KEY 36 TL57LP 36 = Rev # L = Lit U = Unlit 57 = S/C inclination LP = low phase Red = Early Green = upleg Blue = downleg