M33 - Triangulum Galaxy

[AstroScience]

This is my first light with GSO 8" f/8 Ritchey Chretien. I have used it with Astro Physics CCDT67 reducer to get fast f/5.4 scope  and around 1000mm of focal length to widen my imaging options. Although you may find on some vendor websites, that this combination of GSO 8" f8 + CCDT67 + Crop DSLR will give pinpoint stars all around the field - they are wrong. I didn't tested other reduction factors of this Reducer, but at native 0.67x factor the results are unacceptable. There is very strong vignetting with even more field curvature with this setup.

Making this image I had to crop around 20% of the field, which left me with galaxy just fit nicely in the view and still, you can note deformed stars around the corners, meaning, to get perfect image you'll have to crop even more. Using smaller chip size than crop DSLR will probably give better results or choosing smaller object then crop the image leaving just good central area. Anyway, most of the time I plan to use it at native 1624mm focal length for the small galaxies.

More details and full resolution image you can find on my website:

http://www.myastroscience.com/#!m33---triangulum-galaxy/c1oi4

[Jules]

From my iPhone it looks a very nice image, well done.

Julian

[cdesselles]

I agree.  Very nice indeed.

[Zocky]

Excellent image.
To improve it even further, I would add a little contrast to the center of the galaxy, and fix the centers of the brightest stars (they have darker area inside, probably due to the mask).

[Jules]

Looking at it on a computer screen, I think you have a slight green tint.

Julian

[AstroScience]

Thank you guys, for your feedback.

Julian: I'm processing on hardware calibrated monitor, there is no green tint to the image. You can load it in PixInsight and evaluate RGB values at different portions of the image and you will see that the colors is very well balanced.

Zocky: I've been trying Dark Structure Enhance, LHE and contrast curves, but the results were not satisfying to my eye so I felt to leave it at that, giving to it more of a mainstream look.

[Geoff]

Julian: I'm processing on hardware calibrated monitor, there is no green tint to the image. You can load it in PixInsight and evaluate RGB values at different portions of the image and you will see that the colors is very well balanced.

I agree.  Furthermore, using SCNR doesn't change the image background at all.

[lucchett]

The image is very nice in my opinion.
I agree there's something unusual in the colors, did you apply different saturation curves for different colors?
I like the result
Andrea

[pfile]

yeah - i had been using a tele-vue 0.8x reducer/flattener with my AT6RC and had convinced myself that the results were good, when in fact the images showed quite a bit of barrel distortion. it was especially obvious when i used a full-frame DSLR to try to help visualize out to the corners better during collimation. the smaller RCs have a lot of field curvature, but the 0.8x reducer-flattener managed to overcorrect the image a lot. i've stopped using the reducer on that OTA...

anyway this looks darn good even if you had to crop it a little bit.

rob

[AstroScience]

Andrea:Thank you, I have used only color saturation to push the colors. Nothing special. I love how RC got me those colors.

Rob: Thank you, there is a good news. Looking around the web I have found that at native 0.67x reduction the AP CCDT67 reducer givining bad results, but at 0.75 - 0.73x It performs much better. Means I can still reduce that scope to f6 and got much better field. Next time I'm going to try it.