planets and Spica, looking west

Event Date: September 26th
Time: 7:14(.20) PM


Brief

   Our evening sky is host to three planets over the next week, although one of them is soon to fall  completely into the glare of the Sun very soon: Saturn (+0.7).
•A clear, unobstructed horizon is needed to find the "ringed wonder" and even so, optical aid is recommended. 
•Mars, (+1.2) which has been separating from Saturn for the last 6 weeks, is low in the west-southwest. Although dim and far away, Mars can still be a decent telescope target; especially with all the recent news over the last month or so about rover Curiosity up there, millions of miles away.  As we progress through the fall and Mars' prograde motion increases, the geometry of the evening sky will put it at a better apparition, albeit slightly.  We lose the planet to the Sun's glare by mid-late winter.
•Finally, Mercury (-0.5) continues to gradually pull away from the Sun, and still bright enough to see low in the west.  The planets are labeled below, with the star Spica near them, and more info to follow.

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

Detailed

   Although Spica is very low to the horizon, as Mercury is, I included it as a reminder about the triangle configuration that we saw change weekly with Mars and Saturn.  Now, Mars has moved far from it and Saturn, which moves slowly enough to still be about 6 1/2º away.
   Mercury's emergence from the Sun is slow, being further south of it, and setting only 30 minutes later this evening.  We will have to wait about another two weeks to see it clearly, as the Sun continues to set earlier and the declination gap starts to slowly improve between the two.  Using optical aid, try finding elusive Mercury as soon after Sunset as possible, while it is still high enough up, and a high elevation with no obstruction is highly recommended.
Mars sets a little more than two hours after the Sun, and this gap will vary during the next four months, depending on both the declination difference and separation of the two.  As hinted above, with our improving west-sky, evening geometry throughout the fall and most of winter, coupled with Mars' increasing movement in prograde motion, it will seem to stay at a similar altitude at Sunset.  Find out more about that and its path tomorrow.