clear sky chart

Job 9:9

Job 9:9-10
9 He is the Maker of the Bear and Orion,
the Pleiades and the constellations of the south.
10 He performs wonders that cannot be fathomed,
miracles that cannot be counted.

Sunday, March 11, 2012

M81 & M82

On 3/10/12 we had probably the best night for deep sky work this year.  Transparency was clear, and the moon didnt rise till around 11pm.  I had a couple targets in mind, the first was NGC 2403.

I could not get the autoguider tracking very well on this object.  The problem with this region of sky is that there are no bright stars near the object.  Because I'm using an unmodified webcam to guide, I had to offset the guider quite a bit, and the stars were streaking badly.  I took only 5 frames, but I did get this rather poor image, which would suggest that if I can fix my guiding problem, I should get a reasonable image if I was able to take more frames.

Since this object didnt work, I decided to attempt the M81 & M82 pair.  This one came out much better, but would have been even better if I were at a darker site.  Also, in these images, it appears I was not focused perfectly, which will also affect quality.  I was able to clean up much of the capturing problems in post processing, but with quite a bit of difficulty.  This is what I ended up with:

As you can see, this image is much more respectable than the last.  I used 25 frames, each 3 minutes in duration at iso 800.  Telescope is a Celestron C6-NGT at f/5.

Here is an image of M81 alone:

This image came out real nice, because it was cropped out of the above image before processing, and did not have to deal with extreme gradients in the larger image.

These images I used a new beta version of Deep Sky Stacker, which handles short, noisy exposures better than the current stable version.  It also works with my camera raw files directly without having to convert them to Tiff's.  I believe this alone is a  substantial improvement.

The beta version can be downloaded from the yahoo group,

Of course, you have to join this group to download the file, but its well worth it, you can keep abreast of the latest  in DSS, as well as use the group to ask questions as well as report bugs.  In return for testing the software, you get to use a newer version.


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