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Tuesday, August 31, 2010

Sky photos, 8/31/2010

Silently, the wandering objects in the dome of the heavens known as "planets" continue to thunder across the sky.  Venus and the bright star Spica had their closest encounter tonight, and the difference in the positions of these two objects from last night to tonight is quite remarkable.

Due to a cat who chose to hide when it was time to take his medicine, I had to get my images from a different location tonight than I did last night.  This location doesn't have a very clear view of the western sky, and features utility lines and bright streetlights that cause all sorts of internal reflections in my lens.  Here is the uncropped first image I took tonight at 8:24 PM.  You can see what I was up against.


It wasn't great, but a quick zoom of the image showed that I had captured Venus, Spica, and Mars.  Compare this to last night's image, when Venus was to the right of Spica; tonight it is on the left.  Mars, once again, is to the far upper right.



I was able to get quite a few photos, but due to the cumulative glare any composite that combined all of these images would be too washed out to actually show anything.  Here is a composite image of the last ten of my photos, taken between 8:29 and 8:33 PM.  Notice that in the last one, Venus has already partially disappeared among the branches of the evergreen tree.


Now we enter the endgame.  Venus will put more distance between itself and Spica, and will also gradually pull away from Mars.  Mars will pass closest to Spica on the evening of September 5.  According to Guy Ottewell's Astronomical Calendar 2010 (or, more precisely, Fred Schaaf's "Observer's Highlights for September" from this calendar), "Venus pulls away from Mars but retrogrades back to pass 6.5 degrees south of Mars on September 25."  As the month progresses, Venus will brighten considerably and - visible to keen-eyed observers and those with the appropriate observing tools - will increase in diameter while at the same time shrinking down to a thin crescent.  This is one great feature of having a bright planet like Venus on an inside track  with the sun - we get to see it go through phases.  I have never observed phases of Venus myself, but we'll see if I can change that at the end of this month.

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