Archive for June 13, 2014

06/13/2014 – Ephemeris – Saturn’s Rings and the Cassini Division

June 13, 2014 Comments off

Ephemeris for Friday, June 13th.  Today the sun will be up for 15 hours and 31 minutes, setting at 9:28.   The moon, at full today, will rise at 9:54 this evening.  Tomorrow the sun will rise at 5:56.

Saturn rings are the wonder of the solar system.  While we know that Saturn isn’t the only planet with rings.  Jupiter, Uranus, and Neptune have them plus at least one asteroid.  Nowhere are they as grand as at Saturn.  The rings actually outshine the planet.  Now they are opening to their widest extent, and will continue to open a bit more until 2017, before closing again for 7 ½ years.  Last Friday during the star party at Northwestern Michigan College’s Rogers Observatory, I was able to spot the break in the rings called Cassini’s Division.  It’s caused by the orbital resonance of the moon Mimas and the ring particles at that distance from Saturn.  Mimas orbits Saturn once to the ring particles at the division orbiting twice.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.


Saturn and rings

Saturn and rings from the Cassini spacecraft, plus the aurora oval in ultraviolet. Credit: NASA/JPL/Space Science Institute