M13 - Forums - AstroBin

Topic starter

Aug 16, 2021

I have been trying for a long time to decide which version of my M13 I should call the final. I have dozens upon dozens of versions beyond what is posted on Astrobin. I am trying for a realistic look--so not too much saturation, as much resolution as possible. I would be interested to hear which of these versions is better, and why. Or what is wrong with both - maybe I have other versions where I did not make the same mistake. Both images were taken with a C11Edge at F10 (2,800 mm) using unguided 20-sec exposures. Exposure time is about 4.75 hours about equally split between RGB. I took these in summer when I only get about 5 hours of imaging time--and I have had very few clear nights over the last 6 months or so. that is why the total exposure time is not larger. I admit teh difference is subtle. Who knows, with your input maybe I have yet to process the best version. Thanks for looking

Version A

Version B

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David Moore

Aug 16, 2021

I prefer the lower one as the blues and less so the yellows stand out more particularly in the white core. As you say it is subtle and reminds me a bit of the colour blind tests opticians give. They are lovely and sharp particularly the lower one in the core and I like them both.

andrea tasselli

Frequent contributor

Aug 16, 2021

On my monitor they both look too bright in the core robbing some colour saturation. Both show a rather distracting background non-uniformity so you may want to look into it. Having to chose I'd go with the first rather than the second.

Ruben Barbosa

Aug 16, 2021

Hi Rodd,

Can i do some fast and small changes in your M13? You know like the background full of stars....

Rodd Dryfoos

Topic starter

Aug 17, 2021

andrea tasselli:
On my monitor they both look too bright in the core robbing some colour saturation. Both show a rather distracting background non-uniformity so you may want to look into it. Having to chose I'd go with the first rather than the second.

Thank you. My sky stinks so the background is as good as I can make it. As far as brightness, I have versions with flat profiles but globular clusters ARE bright in the core. Most images have no star resolution or colors in the core at all. If you look at a globular cluster in the eyepiece, it will look like these with a glaring core. That is what I am after. Reslistic

Helpful Concise

Rodd Dryfoos

Topic starter

Aug 17, 2021

Ruben Barbosa:
Hi Rodd,

Can i do some fast and small changes in your M13? You know like the background full of stars....

That looks like the globular cluster is smaller. The little blue center looks funny to me. I don’t think you have more stars than mine. You just reduced the size of the core brightness

Rodd Dryfoos

Topic starter

Aug 17, 2021

I prefer the lower one as the blues and less so the yellows stand out more particularly in the white core. As you say it is subtle and reminds me a bit of the colour blind tests opticians give. They are lovely and sharp particularly the lower one in the core and I like them both.

that is the way I am leaning as well

Rodd Dryfoos

Topic starter

Aug 17, 2021

herr I’d one with a flat profile. I like it, but it lacks the inherent power and brightness of a globular cluster

Rodd Dryfoos

Topic starter

Aug 17, 2021

andrea tasselli:
On my monitor they both look too bright in the core robbing some colour saturation. Both show a rather distracting background non-uniformity so you may want to look into it. Having to chose I'd go with the first rather than the second.

not sure what you mean about you background, really. Looks good to me. If you visit my page and find this image you can look in full resolution. The color in the background is balanced and it looks smooth to me. Maybe it’s the faint stars you see? They are supposed to be there

andrea tasselli

Frequent contributor

Aug 17, 2021

I suppose it is all in the eye of the beholder. To me this one is way better than any of those before. The problem you have is that it is somewhat lacking context as the field is very restricted so there is no way you can contrast it against the background field. But again, to each his/her own…

Rodd Dryfoos

Topic starter

Aug 17, 2021

andrea tasselli:
I suppose it is all in the eye of the beholder. To me this one is way better than any of those before. The problem you have is that it is somewhat lacking context as the field is very restricted so there is no way you can contrast it against the background field. But again, to each his/her own..

you are right. But this image was taken at a focal length of 2800mm with a relatively small sensor. My goal was a close in shot of the cluster, paying homage to Hubble, so a mosaic was not what I wanted to do. Besides, with the number of clear nights I get, mosaics take forever. I did this with a wider FOV previously. This one explores the core

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