Another image from SRO in California. I have a backlog of data from last summer and autumn before the weather turned to crap like spring/summer in Brisbane
Sharpless 2-132 is an emission nebula on the border of Cepheus and Lacerta. It's not that bright and exciting but I did what I could with it. This is a roughly Hubble palette image. I didn't have any RGB data so I mangled the Hubble data to provide some vaguely pleasing star colours - better than white anyway.
The color channels are great. But the stars look a little weird, compressed. Great object with lots of detail. Rarely do you see this in narrowband.
j
Thanks, John. I did use an experimental technique to give the stars a little colour and they didn't turn out as well as I hoped. Might have to play around with that some more.
Quote:
Originally Posted by multiweb
Pretty cool, Rick. Never seen this one before. Looks like a messed up M17 on its side. Nice nebula.
An interesting object. Nice colour work. The stars though have been badly damaged along the way and they grab your attention. It'd be better to have magenta stars.
I know of 2 ways of handling the magenta stars. The first does not always work and that is simply reducing magenta using the selective colour tool.
The other is selecting the stars and using the swap channels tool in Photoshop. Another would be to select the stars and then manipulate the colour (if you select accurately enough it does not affect the surrounding nebula too much but it does a bit).
No free lunches with stars in narrowband and as you point out its best to get colour data for the stars and blend in.
I used JPM's tone map process which I have adapted to PixInsight, so the stars were originally white. Maybe they would have been better left that way. I'll see if I can get the false colour thing to work better. If not I'll consider it a failed experiment and go back to white stars
I used JPM's tone map process which I have adapted to PixInsight, so the stars were originally white. Maybe they would have been better left that way. I'll see if I can get the false colour thing to work better. If not I'll consider it a failed experiment and go back to white stars
Cheers,
Rick.
Perhaps a mask for the stars whilst the mapping process is done to protect them from changes. Or extract the stars as a layer and save that only then do the mapping then add the stars back in later when all the colour work is complete.
Perhaps a mask for the stars whilst the mapping process is done to protect them from changes. Or extract the stars as a layer and save that only then do the mapping then add the stars back in later when all the colour work is complete.
That's pretty much what I did, Greg. The tone map process is based on star removal. The stars are added back as part of the luminance after all the colour work is done. I then did some further processing on the stars to attempt to add some colour which is probably what was responsible for mangling them.
Sorry Ricki, you know I love your work but not a big fan of this one
The stars don't look natural and are all uniform and pale, the neb looks slightly posterised and the colours are a bit washed out and weird....hmmm? is that enough negative critique..?
Having said all that encouraging prose, it has some great details and does look like an amazing area, with huuuge potential in a repro though
Going to have to agree with Mike on this one Rick - sorry. The stars are insipid and they look like they've taken on the colour of the nebulosity. I would let the NB stars shine through in all their glory ... let them be magenta!!
Really nice Rick, this is a difficult target, so faint !!!
If you need RGB for stars i have one rendition about in my web site, i found terrific to keep calm the stars.
Sorry Ricki, you know I love your work but not a big fan of this one
The stars don't look natural and are all uniform and pale, the neb looks slightly posterised and the colours are a bit washed out and weird....hmmm? is that enough negative critique..?
Having said all that encouraging prose, it has some great details and does look like an amazing area, with huuuge potential in a repro though
Mike
Thanks for the critique, Mike. Watch out for the repro...
Quote:
Originally Posted by marc4darkskies
Going to have to agree with Mike on this one Rick - sorry. The stars are insipid and they look like they've taken on the colour of the nebulosity. I would let the NB stars shine through in all their glory ... let them be magenta!!
No magenta, Marcus, but maybe I'll return them to the original white, or...
Quote:
Originally Posted by Leonardo70
Really nice Rick, this is a difficult target, so faint !!!
If you need RGB for stars i have one rendition about in my web site, i found terrific to keep calm the stars.
All the best,
Leo
Thanks Leo for the kind comment. I might take you up on that offer of RGB stars!
I have posted a new revision with the white stars that the tone mapping process produces instead of my previous attempt at fake star colour. Next time I'll make sure to get some RGB.
Leo: thanks for the kind offer of RGB stars but unfortunately your image doesn't cover one corner of my FOV, so I'd have to do an odd crop.
Thanks, Mike. I'm guessing you're still not a huge fan. That's cool... I don't think I am either I haven't seen an image of this object that I think is really great. There are some areas that I think would look good at longer focal length.
but not a big fan of this one 
