Triffid Nebula revisited

leinad (Dan) · #1 10-03-2010, 02:47 AM

Hard to believe it's been a year since I last imaged the Triffid Nebula, and finally I have my imaging system close to where I want it.
Now I need to focus more on my processing skills and post processing.

This is from a stack of 25x10min with the QHY8, VC200L at F/9.
Calibrated with 20 bias, 20 flats.
Cropped to remove apparent vignetting. Processed in PS and CCDStack.

It was a half moon weekend when captured, and the moon being ~20degrees from the Triffid during the night and the sky washed with moon glow I was quite surprised how much data I captured.

Not overly happy with the processing as yet; lots to learn and practice.
Though I'd share to get the Triffid season started

Warning: 1.2MB file.

Feedback welcomed.

http://i611.photobucket.com/albums/t...al2_pp_fnl.jpg

Grahame (Grahame) · #2 10-03-2010, 04:10 AM

Nice work!

AlexN · #3 10-03-2010, 06:39 AM

Awesome! Talk about up close and personal..

Really nice image Daniel, Bet you're stoked!

iceman (Mike) · #4 10-03-2010, 06:42 AM

I really like that, nice work indeed. I'd be very happy with that!

telecasterguru (Frank) · #5 10-03-2010, 07:02 AM

Well done nice image.

Frank

multiweb (Marc) · #6 10-03-2010, 10:34 AM

Wow! Very nice colors and beautiful details. Maybe a tad clipped in the processing but great pic.

TrevorW · #7 10-03-2010, 11:01 AM

Good one Dan

leinad (Dan) · #8 10-03-2010, 12:16 PM

Thanks everyone.

I agree Marc, a bit too clipped I think. I wasn't working on my Dell 27" which has great color channels for working on, but this was done on my laptop which overcorrects the blacks. I can see here on this work monitor that in fact the dark areas are hard black

When I ran a deconvolution in CDDStack and final process in PS, It seemed to clip the colors and there was no going back.. I didn't incrementally savethe stages of processing ! Doh.

Lesson learned

One interesting thing I found is that I had a total of 40 flat frames from two nights(20 each) and 40 bias frames as well. When I stacked with the 40 flats frames this caused a light vignetting; yet when I only used the 20 from the first night it was much less aggressive.

multiweb (Marc) · #9 10-03-2010, 12:35 PM

Quote:

Originally Posted by leinad

When I ran a deconvolution in CDDStack and final process in PS, It seemed to clip the colors and there was no going back.

Yeah CCDStack will do that when you save as a scaled 16bit TIFF. So just before you save drop the background slider 10-20 counts and increase the DDP by the same amount. You'll get all your histogram then when saving and you can narrow it back in PS at the end of your processing.

or....

If you're already in PS you can use the shadow highlight tool to expand your histogram boundaries. You can salvage the pic this way too (sort of)

leinad (Dan) · #10 10-03-2010, 12:41 PM

Quote:

Originally Posted by multiweb

Yeah CCDStack will do that when you save as a scaled 16bit TIFF. So just before you save drop the background slider 10-20 counts and increase the DDP by the same amount. You'll get all your histogram then when saving and you can narrow it back in PS at the end of your processing.

or....

If you're already in PS you can use the shadow highlight tool to expand your histogram boundaries. You can salvage the pic this way too (sort of)

Cheers, I'll check this out. Puzzled me why CCDStack autoscale darkens the image as much as it does during import, compared to how it was when saved from PS.