Wednesday, January 6, 2010


Mars is approaching!  Closest ever!  Big as the full moon!  Well, at least that is what the email your crazy uncle forwarded to you would have you believe.  The truth is that Mars is approaching its closest point to Earth during its current orbit around the sun...only, its not all that close for visual observation.  In 2003 when Mars was extremely close it reached an apparent diameter of almost 25 arcseconds.  Tonight, a few weeks before closest approach, Mars is a scant 13.1 arcseconds in diameter.  Consider that the full moon is about a half degree in diameter (or 1800 arcseconds) and you can appreciate that those emails your old uncle keeps forwarding are in fact an internet hoax.

Mars is a difficult object to observe visually as its features are dusky and low contrast. Seeing them is highly dependent on practice, patience, and even more importantly the atmospheric stability at your observing location.  Tonight proved to be a decent night at the Lost Pleiad Observatory.  Two mild days with little change in the weather made for a relatively stable night with good transparency.  As evidence, I was able to observe the A through F stars in the trapezium easily at 122x in my 5.5" refractor.  There was minimal dust in the air and the moon had not risen during my observation of Mars.  I am working on finding a good technique for sketching Mars, including finding the right pencils and smudging tool (fingers!).  Soon, I will have to learn how to better scan my images so that they do not show you every stray bit of graphite on the paper that are invisible on the original.

Instrument: 140mm Refractor at F/7
Eyepiece: 4mm Nagler Zoom (245x)
Time of sketch: 0500-0525 UT, 1/6/10 (10-10:25 PM MST, 1/5/10)

RA: 9h 26m 11.8s
Dec: 19 deg 15' 29"
Central Meridian: 330
Constellation: Leo

Syrtis Major is obvious, as is the collar below the north polar cap.  Interestingly, the Hellas Basin is visible as a bright area south of Syrtis Major.  (I believe that the feature to the right is Sinous Sabeous, but I need to locate a good map of Mars)

Illumination: 97.3%
Magnitude: -.9
Distance: .7138 AU (That is 5.9 light minutes away!)
Size: 13.1 arcseconds

Here is a simulated image of Mars from the freeware program Winjupos

That's all for tonight, I will post more on Mars in the coming days, including some of my sketches from 2003 when Mars was really close...

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