Mars closing-in on Saturn & Spica

Event Date: July 22nd
Time: 9:00 PM


Brief

Mars continues to gain on Saturn, and now less than 13º apart.  As Saturn moves much more slowly in prograde motion, it is gradually closing in on Spica for their last close encounter of this revolution for Saturn.  I will mention more of that in the detailed in about three or four weeks prior to their closest conjunction.  For now, I will show the planets and Spica with the Moon west of them, setting and waxing as a 17% crescent at the time above.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

 For months now, as a result of prograde and retrograde motion and the difference in ecliptic latitudes, Spica and Saturn have had a variety of separations.  Since late fall, it has ranged from just under 5º to 7º, so always binocular-friendly during that time.  In a little over 2 weeks, after one more separation of under 5º, the separations increase each year for about the next 14; about half a revolution for Saturn.  Only its retrogrades will bring it a little closer each time to Spica, while its prograde motions move it further east until opposite the star on the celestial dome.
   Look at the image one more time: what is that bright star above Mars similar in color?  The answer is tomorrow, and why it is important to keep track of it setting in the west during these later summer weeks until season's end.