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Eclipses of Saturn's Satellite Rhea during 2008


Eclipses of Rhea during 2008.

Events of Saturn's Satellites Rhea and Titan

Eclipses of the satellites of Saturn only occur for a year or two near the time when Saturn's rings are edge on to the Sun. This next occurs on 2009 August 10.

Saturn's satellites are a lot fainter than the four Galilean satellites of Jupiter, only eclipses of the two brightest, Titan (magnitude 8.6) and Rhea (magnitude 9.9) are likely to be observable through a small telescope. The inner satellites are fainter still and eclipses will occur close to Saturn's disk, making them difficult events.

Eclipses of Rhea start in July 2008 and then occur at intervals of approximately 4.5 days. Those of Titan, which is considerably further from Saturn than Rhea, do not start until 2009. The table shows the times of eclipses of Rhea during 2008. All eclipses are shown, whether they are visible from New Zealand or not.

The first few occur with Rhea a little to the south of Saturn so both the disappearance and reappearance of Rhea are visible. In fact by July, Saturn is getting close to conjunction so is low in the evening sky setting mid evening. As a result only the first eclipse on July 5 is likely to be observable from New Zealand, and Saturn will be getting low for that event. Apart from that event, New Zealand observers will have to wait until 2009 to see any eclipses of Rhea.

Saturn is at conjunction with the Sun on September 4 and will be too close to the Sun for observation about a month either side of that date. After conjunction only the disappearance of Rhea into eclipse will be visible from the Earth, the reappearance takes place while Rhea is occulted by Saturn. In the table of events, the times of occultation reappearance are shown, shaded in grey. It is not likely this event would be visible in a small telescope against the bright limb of the planet.

Table of eclipses of Rhea for 2008

After conjunction in September, Rhea reappears from eclipse while it is behind Saturn as seen from the Earth. The times of occultation reappearance, when Rhea emerges from behind Saturn are shown instead.

Times of events are adapted from those given by Dave Herald's OCCULT 4 program.


Date Time UT Date Time UT
Disappearance Reappearance Disappearance Reappearance
July 5 08:01 08:33 July 9 20:21 21:11
July 14 08:43 09:45 July 18 21:07 22:18
July 23 09:30 10:51 July 27 21:55 23:23
August 1 10:20 11:54 August 5/6 22:44 00:25
September 4, Saturn at conjunction with Sun
Date Time UT Date Time UT
Disappearance Occultation Reap. Disappearance Occultation Reap.
October 8 04:44 08:35 October 12 17:10 21:10
October 17 05:36 09:45 October 21 18:02 22:20
October 26 06:28 10:53 October 30 18:54 23:27
November 4 07:20 12:00 November 8/9 19:46 00:32
November 13 08:12 13:03 November 17/18 20:38 01:34
November 22 09:04 14:05 November 26/27 21:30 02:34
December 1 09:56 15:04 December 5/6 22:22 03:32
December 10 10:48 16:00 December 14/15 23:15 04:27
December 19 11:41 16:54 December 24 00:07 05:20
December 28 12:33 17:46 2009 January 2 01:00 06:11

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