Downtown Cygnus Revisited

[Knight of Clear Skies]

Feeling pretty ropey today but at least staying in has given me some time to process some images. I wasn't really satisfied with my September effort on Cygnus, I got too greedy on the lens aperture and the processing was a bit ropey, so I had another go with my 50mm lens earlier this month.

Taken with a 50mm f1.4 SMC Takumar lens at f4 on a modded Canon 1100D camera, riding on my EQ3-2 mount. ~1 hour 30 minutes total exposure using 3m30s subs, 30 dark bias but no darks or flats. Much happier with this version, the corner star are much better and the nebulosity is coming through much better thanks to the isolate filter in StarTools. I'm in two minds on whether to back off on the saturation a bit, I'd welcome any thoughts. Click for a larger version on Flickr, features such as the Crescent nebula are hiding in there.

Also, here's a synthetic (i.e fake) Ha version, taken by converting the red channel only to monochrome.

It's fun to compare this with a real Ha shot of the same region, as you'd expect the filter allows much more of the fainter structure to come through.

As a bonus, here's a reprocessed version of the NA & Pelican at 200mm/f2.8, about 40 minutes of data.

[laudropb]

Very nice images. Thanks for posting.

[wimvb]

Very nice indeed. Lots of nebulosity. I didn't know there was so much going on in Cygnus.

The bottom image of NA seems posterized. What software did you use?

[Knight of Clear Skies]

Thanks all.

The bottom image of NA seems posterized. What software did you use?

Is that good or bad? I used StarTools for most of the processing, I'm not sure now exactly what I did to it.

Here's a toned down version of the 50mm shot if anyone is interested, less nebulosity showing but I prefer it.

[wimvb]

I like your toned down version of Cygnus.

The posterized look of NA may be due to stretching (too) much. IMO image processing is always a mix of trying to achieve realism and personal taste. What we are pleased with as astrophotographers may change over time as we develope skills and personal touch. So, what is pleasing to one person, may seem underworked or overworked by Another.

Anyway, I think your images were very good, and I like the way you captured the details.

Thanks again for sharing.

[Knight of Clear Skies]

Thanks for the feedback. Sometimes I need to step away from an image and go back to it with a fresh eye, it's very easy to get carried away pushing one feature to the detriment of others I find. My processing skills are a little crude at the moment, I can't isolate features well and my workflow is erratic, but I feel I'm making good progress.

I'm pretty happy with the NA & Pelican image myself but it's useful to hear you find it too much, I'll have another look at the histogram. For me the star shapes are it's biggest problem, I'm still experimenting with how to get the best out of my 200mm L lens. I can't get it to work with a bahtinov mask for some reason, so I might try the focus aid in APT.

[wxsatuser]

I would'nt worry to much, like any photos/art, some will like it some won't.

If you want to be totally correct on colour you will need to know the chemical compostion

of each target and adjust accordingly.

Here is my interpretation of the same area, slightly more red and blue, is it right, most likely not.

For the moment I like it until I have another go at it.

[Knight of Clear Skies]

Nice image, lots of nebulosity showing there. What's the exposure and did you use any filters please?

I'm not worried about true accuracy, just trying to improve my processing skills. I'm enjoying myself, looking for flaws in my images doesn't stop me appreciating them.

[wxsatuser]

Nice image, lots of nebulosity showing there. What's the exposure and did you use any filters please?

I'm not worried about true accuracy, just trying to improve my processing skills. I'm enjoying myself, looking for flaws in my images doesn't stop me appreciating them.

Stack of 10x300secs at f2.8 with a Sigma 17-50mm zoom on 50mm, Canon 60Da with Astronomik CLS clip.

The Sigma has 'flying birds' around the edges, this was a test to see how it was with stars.

I was struggling with colour calibration but I find background neutralisation followed by colour calibration and DBE in

Pixinsight gets near but I am still experimenting with it.

For stretching I find a Screen transer function applied to the histogram pushes the exposure to about the right

limit and I don't have to mess with the curves later.

[Owmuchonomy]

Thanks all.

Is that good or bad? I used StarTools for most of the processing, I'm not sure now exactly what I did to it.

Here's a toned down version of the 50mm shot if anyone is interested, less nebulosity showing but I prefer it.

Very nice wide field.  What ISO did you choose for this one?

[Knight of Clear Skies]

Very nice wide field.  What ISO did you choose for this one?

Thanks. I shot this at ISO 800 and f4, I only use ISO 1600 with the slow kit lens these days.