September 29, 2007

M27 June 2007


In late June we had a brief break in the monsoon---one night of clear skies, not very transparent, until around 3 am. I used the Orion 100mm achromat, the LXD75, and the DSI Pro. Once again, the exposures were unguided. This image is a combination of 239 2-second exposures and 131 2.8-second exposures; that is just over 14 minutes total. The exposures were dark-subtracted, combined, and processed entirely in Envisage. The result shows less detail than I had hoped, probably because I was so excited to get set up and start taking pictures that I forgot to install the V-block filter in the achromat. That may explain why some of the stars are so large. Also, I was still learning the software, and I saved the individual frames in a format that made them harder to process afterward. Moreover, transparency was not great. As I stretched the histogram, I found that, in order to make the background black, I had to sacrifice lots of nebular brightness. Finally, I took this from my backyard, which sports Bortle scale 4.5-5 skies.

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