Tuesday, November 30, 2010

Thanksgiving Family Star Party

This Thanksgiving holiday, we went back to visit family in Las Cruces, NM.  While there, I setup an impromptu star party in my father's backyard.   The city street lights did not make for great deep-sky observation but we all had a peek at a few interesting objects including Jupiter and Orion.

While observing Jupiter, I noticed that a moon shadow was transiting the surface.  After everyone had seen it visually, I plugged in a webcam and was able to get a nice sequence of not only the moon shadow but also the moon itself passing beyond the limb of Jupiter.  Later looked it up to determine it was Io.

Saturday, November 6, 2010

Comet 103P/Hartley

This evening, I imaged a periodic comet, 103P/Hartley from the backyard observatory.  Per the Wikipedia article, the Deep Impact spacecraft approach within 700km of this comet and imaged it close up, showing an asymmetrical dumbbell shape about 1.5km in diameter. It made its recent perihelion approach on October 28 and is on its way back out through the solar-system.

I imaged the comet with a TMB-130SS 5" refractor and a QSI-540ws cooled CCD.  I stacked 7 frames, each a 30s exposure.  I processed the stars and comet core separately.  In the first pass, I aligned on the stars and subtracted out the comet.  In the second pass, I aligned on the comet core and let the median filter remove the stars.  The two images were then stacked for the final result.  The coma shows up very clearly and the stars remain sharp.   The comet has a hint of a tail pointing to the left.