Wednesday, March 28, 2012

Observing Leftovers...

A couple posts ago I talked about how the seeing improved from one night to the next.  It made sense to only post the common images between the nights, so a fuzzy Saturn was compared to a much nicer one from Friday.  But in the hours before we turned to Saturn, a couple friends shared imaging time with us, so am presenting a few more frames from that evening.

After doing a little visual observing of some of the showpieces in the sky, we attached DSLRs (in this case a Canon XSi) to the Takahashi 106 that rides piggyback on the 20" telescope we were using.  This first image is of the beautiful galaxy pair Messier 81 and 82.  At about 12 million light years distance from us, it is not considered part of the "local group" that includes the Milky Way (us) and the Andromeda Galaxy, but are just about the nearest galaxies just outside our neighborhood.  The trio consists of M82 on top, M81 at bottom right and NGC3077 at lower left.  Also, just barely seen to the left of M81 is a small dwarf companion galaxy Holmberg IX.  Realize that this is a stack of 4 exposures of 3 minutes each - a minuscule amount of time for such a nice result.  Our friend George Hatfield did the image collection and stacking of this object.

Located only a few degrees away from the above galaxy trio, the comet 2009P1 Garradd has continued to put on a good show.  Discovered nearly 2.5 years ago, it has remained just below naked-eye visibility since last fall.  Even now it is about as close as it will get to the earth (1.25 times the earth-sun distance) and is visible in binoculars in a dark sky.  With a modest exposure - here 5 stacked 3 minute exposures, show the comet's motion in the 15 minutes (I stacked the comet image, so the stars are trailed), as well as the comet's 2 tails.  While most comets are lucky to have one tail, this one has a bluish ion tail that is pushed straight back by the solar wind.  The yellowish tail is if larger particles that trail behind the comet as it moves in its orbit.  When the earth is close to the comet's orbital plane, both tails can be seen, often pointing in different directions!

Finally, the big news in the previous week (16 March discovery) was a bright supernova in the galaxy Messier 95.  Located about 35 million light years away the supernova is shining with a brightness that is a large percentage of the entire galaxy!  There is no way that an amateur sized telescope can spot a single star at that distance, yet this supernova can be easily seen in an 8" telescope.  With the 106mm Takahashi (530mm focal length), you get not only Messier 95, but also its neighbor M96 and another galaxy cluster in the upper left of the field.  This is 12 minutes of total exposure with 4 frames.  Now near maximum brightness, in the next few weeks the supernova will start to fade, and it will become invisible to us inside of 4 or 5 months with this telescope, at least.

Those were our observing highlights from last Friday.  Thanks to the Nightly Observing Program/NOAO/NSF for access to the 20" telescope.  It is a spectacular venue and I'll try to schedule these after-hours sessions in the future as my and its schedule permits.

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