M81 and M82

Comment

Comment by Joshua Forschen on May 31, 2012 at 1:59am

I'm going to search out that processing video where it goes step-by-step on M31. I've forgotten a lot of how to process since I don't get a lot of chances to pull the scope out in Germany because of the fantastic crappy weather.

Last night, I tried shooting this M81 again. This time, I did 60 frames of 2 minute exposures at ISO 1600. Turned out horrible. Only the core was visible and the arms barely came out. I'm a bit frustrated right now and this seems totally opposite than what I should be seeing. The difference this time is my histogram was stacked to the right instead of to the far left on my purple shots.

I think I need a few days of drinking before I try at this again. Thought I was close at getting the hang of part of this. lol

Comment by Russ Ruggles on May 30, 2012 at 2:00pm

OK - I see part of your issue
GXT - you need to adjust your settings.
First, make sure you are not running GXT over your DSO. Lasso it and then Inverse your selection so everythign but the DSO is selected. Then run GXT at Med/Low with the "Balance colors" box checked.
After that's done - de-select everything.
Now use the Wand to select the background - you should get "marching ants" around most of the stars. Lasso the DSO the remove it from the selected background. You should have a nice lasso around it.
Now run GXT with High/Fine (Both top boxes) and the color balance box is still checked.
That should give you a nice even grey background.
If you joined that group I was talking about you'd fine a video or two there that explains this GXT procedure better. Plus the think the GXT website has something similar.

Comment by Joshua Forschen on May 30, 2012 at 10:08am

I use GXT twice. First pass at medium/medium and then at fine/low. If I hit it again, the picture goes to crud.

I tried stacking this again with white balance options unchecked and it was better but now much. The core wasn't purple anymore but that was it. The dust lanes and everything else in the picture was purple. If it's clear for me tonight I'm going to go for it again.

Comment by Russ Ruggles on May 30, 2012 at 5:22am

Experiment with DSS. If you save your file list you can easily reload all the images used for a stack, make an adjustment and try it again.
I was asking about GXT because it looks like you still have a gradient in your image.

Comment by Joshua Forschen on May 30, 2012 at 3:17am

Russ, I do own a copy of GradientXTerminator, I use it all the time. I know that DSS has an option to use white balances, should I tell DSS to forget about it?

Comment by Marc Basti on May 29, 2012 at 5:03pm

Joshua, good pic in there once you get your color sorted. Nice details, Marc

Comment by Russ Ruggles on May 29, 2012 at 3:37pm

Something you could try is NOT using the white balance in the RAW images and just fix it in PS. Do you own a copy of GradientXTerminator

Comment by Joshua Forschen on May 29, 2012 at 3:27pm

I found the problem. When I pulled up an original RAW in Photoshop, the image's temperature was not showing Daylight setting but a much cooler temperature. When I set it to daylight, the colors came back. I know M82 doesn't have a lot of color in it, but I know M82 should have some color in it. I tried adjusting all of the image's temperature and stack them, but they don't come out very clean. I'll just chalk this one up to a "Doh!" and try it again on cear skies.

Comment by Joshua Forschen on May 29, 2012 at 12:56pm

Thanks for the advice, I'll check it out!

Comment by Russ Ruggles on May 29, 2012 at 12:22pm

Josh,
You should consider joining this group ( dslr_astro_image_processing ) in the Yahoo groups. I've learned a lot in this group - more than I've learned reading and watching DVD on processing.

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