A tale of two images.. Last night, I was working on my Astronomical League (AL) Flat Galaxy (aka Edge-On Galaxies) observations, and one of my targets was NGC 2820. You can see the resultant image of that observation here: http://www.az-dahut.net/Obs-Log-Sheets/NGC-2820-01172015.jpg The actual target is inside the circle, basically in the center area of the image. It was an interesting image, in that the lower right of the image caught my eye, and held my interest more than the primary target. In the lower right is NGC 2805. That was NOT the target, but was captured as a "in the field of view" item. I checked my index of images, and sure enough, I had one for NGC 2805. I had made that observation on April 29, 2013, for the Herschel-2 program. I went and took a look. You can see it here: http://www.az-dahut.net/Obs-Log-Sheets/NGC-2805-04292013.jpg Yup, that was it. But WOW !! What a difference. Therein begins the tale of two images. In April 2013, I was using an LX-200 8" (Alt/AZ). Same camera, but the older image was set to inner-half (think "close up"). I no longer use that setting. I really enjoy looking at the wider view, and the surrounding skies for each object. You miss a lot with close ups (IMHO). Today, I am using a Celestron 8" Edge, mounted on a CGEM (EQ). The difference between Alt/AZ and EQ is a major part of the difference in the images. I was limited to 2-3 minute exposures with the Alt/AZ, and the longer exposures always generated some star drift. With the CGEM (EQ), I can go out to 20 min plus with no problems. My standard for imaging DSO is 5 minute exposures, and a stack of 7 images. And changes in processing tools, and skills. CCDStack-2 is a marvelous tool. Thanks to Adam Block for his lectures on how to use that tool. Late last year, I learned about using dithering with the stack, and now I always do a "Data Reject" clip min/max." Another major change (improvement). PS CS3 is still a valuable "finishing up" tool as well. Amazingly, I have a better image of NGC-2805 today, captured "by chance" as background, than when it was the primary target in 2013. As the saying goes.. Ahhhhhhh, what a difference a day (or year or two) makes. It was an interesting observation to me (the two images, and the differences, and why).. Thought I would share the experience. David M. Douglass dmdouglass@xxxxxxxxxxxxxxx (secondary) david@xxxxxxxxxxxxxxx (main) Cell (602) 908-9092 -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.