M33 - pinwheel indeed (lowenthalm)

M33 - pinwheel indeed

I thought I would use M33 as a test target of different gain settings for my camera during my dark sky outing. As it turned out, seeing was pretty darn good and the images were far too good for just "tests". I don't think I will do much better until an exceptional seeing night. This is a stack of two images, one at about 15x the exposure of the other. After color balancing the images and then adjusting them to better match in exposure, I stacked them with DSS to produce this combined image. I fudged the adjustment a little to favor the crisper image during stacking. Unfortunately, I had to crop out some of the stacked image because it was lost to image rotation because of M33's altitude in the sky. The galaxy was at about 65 degrees altitude during each of the two 5 minute exposures that are combined here.

Lots of detail visible. I especially like the loops in the red emission nebula, NGC 604, on the far left. It reminds me of images I have seen of the Tarantula Nebula.

I usually try to take a minimalist approach to image prep: First, I let DSS take care of the color blanace and RGB alignment. Next, I finalize the image in GIMP: I pulled contrast up with levels and then fine tuned with curves just short of image noise becoming too apparent. Then I rotated to better frame the target for the final cropping and also to soften the image noise. Next I tapped it with a little increase in saturation to bring out the red emission nebula and finally sharpened a little more than what was need to recover from the blurring effect of the image rotation step.

I am going to be spending a few hours analyzing this image, identifying nebula, GCs, and maybe look for some variable stars by comparing it to some of my previous images I have in my archive from earlier in the year!

Original
Final
B

B

Description: The original image was processed with GIMP. Here, I have reprocessed the stacked image with Fitswork 4, improving white balance and contrast, along with a little wavelet filter sharpening.

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Astrophotography with Dobson

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Status	Advanced success
Started	...
Astrometry.net job	2343882
PixInsight job	XOC4LDT5GG8VHME56OVGJTDCUH94TMLB
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	01h33m48s.362
RA (top/left)	01h33m49s.989
RA (top/right)	01h32m33s.105
RA (bottom/right)	01h33m46s.615
RA (bottom/left)	01h35m03s.643

Dec (center)	+30°38′48″.42
Dec (top/left)	+30°57′06″.24
Dec (top/right)	+30°30′13″.60
Dec (bottom/right)	+30°20′29″.47
Dec (bottom/left)	+30°47′19″.43

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