StarTools

Finally some clear nights in a row AND basically no moon. After struggling with M 20 being so close to the horizon I aimed for a target higher up in the sky. Stuff in Cygnus is always rewarding and I only had an image of the Pelican under full moon until now. It contained only duo NB data, was pretty washed out and showed some ugly halos. So it was time to revisit:


I am pretty happy with the outcome. I've been unsure about the colors especially when in NBAccent. Should I discard OIII completely? Balmer purple or pure red for Ha? In the end I left some OIII in (with the cyan option) and chose the Balmer series option. Maybe I'll do a reprocess with different coloring. But for the time being this will do.

See https://www.astrobin.com/w0fan0/ for details.

By the way, this has been the result with only broadband:


The stack contained a sub with a mean satellite streak which was discarded for the final image. But not bad overall in my eyes. For only ~5 hours broadband instead of 5 hours broadband plus 10 hours duo NB there's quite some nebulosity.

Best regards
Stefan

A lot of great detail, Stefan! Sure an improvement compared to your old image. Pinpoint sharp stars.

Stefan B wrote: ↑Thu Aug 01, 2024 8:53 pm I've been unsure about the colors especially when in NBAccent. Should I discard OIII completely? Balmer purple or pure red for Ha? In the end I left some OIII in (with the cyan option) and chose the Balmer series option.

This object contains a noticeable amount of OIII and yes - I too would try to show it. The window of your L-eNhance filter comprises OIII and Hb as well and thus choosing the Balmer Series representation is just fine. I guess. And, of course, it does not burn your eyes like pure red

Best regards, Dietmar.

decay wrote: ↑Fri Aug 02, 2024 2:24 pm And, of course, it does not burn your eyes like pure red

True, pure red is really intense. On the other hand, the current color lools somewhat "dirty". There's maybe a better way....probably I'll try again.

CS Stefan

Here's the "burn your eyes" rendition with Ha being displayed in pure red:


And here's something I haven't done in a while - a H(HO)O version:


I got a bit tired of my H(HO)O images so I stopped making them but this turned out okay, I think. The Ha part in the lower right could stand out a bit more but I already pushed it quite a bit in the Filter module (which I also hadn't used for quite some time) and I didn't want to cheat too much. The image would probably benefit from broadband stars (which I have the data for)... but to get the mask right for layering/blending is such a demanding job...

CS
Stefan

Hi Stefan,

I think I still like the first version best. The pure red version - yes, colouring is a matter of taste but more importantly it lacks the differentiation between the stronger Ha part of 'nose' of the pelican and the other areas. The H(HO)O version of course shows the strongest differentiation. Quite nice. But I'm too still not sure about this layering of broadband stars into it. Feels somehow wrong to me.

Dietmar.

Hi Stefan, meanwhile I revisited your image revisions on AB and I have to admit, the 'pure red' version is somehow the most impressive. It's so difficult to decide between them

Best regards, Dietmar.

Hi Dietmar,

100% agreement with you. The pure red version shows the least amount of differentiation but is most appealing to me.

I always liked the blending of RGB stars into NB images. It avoids the mostly blue colored stars. But the fiddling with the mask is ... Another possibility to get rid of the blue stars is to desaturate the stars and make them white. Looks better to me but you still need a mask.

Regards
Stefan

Just for completeness sake: My 'final' version of the Pelican. It's basically the first NBAccent version with Balmer series. But I pushed the reds more to pink via selective color adjustment tool in PS. Not sure what that's doing to the image in terms of documentary value but it looks more pleasing to me while at the same time still allowing to see the difference in composition between the nebula structures in the lower right part and the other parts of the nebula.