Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST...

Questions and answers about processing in StarTools and how to accomplish certain tasks.
Mike in Rancho
Posts: 1166
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST

Post by Mike in Rancho »

admin wrote: Tue Aug 03, 2021 12:42 am
FWIW, this is super quick process of JohnnyBravo's data from the CN thread you posted;

Good detail should be visible throughout the dynamic range.
According to the coloring, yellow corresponds to areas of strong Ha and S-II emissions; you should be able to see detail in those areas is not particularly compromised vs any other renditions.

I'm not sure what other people in the thread did in their workflows, so I can't really comment on rendition/color validity from a documentary view. I did notice someone mention a way in PI to get rid of purple using SCNR. That same technique can be performed in StarTools (though Tracking will have to be off!).

Go into the Layer module, choose the Invert Foreground Layer mode, Keep. Launch the Color module (Tracking off!), set Cap Green to however much you wish to reduce the purple (you can nuke it altogether with 100%). Keep. Go into the Layer module, choose the Invert Foreground Layer mode, Keep.

Hope that helps!
Thanks Ivo! I forgot all about the possibility of changing the Style and LRGB Emulation settings. So many controls to keep track of. :thumbsup:

I just took my finished tiff back into ST as a stretched image and fiddled with the Color module, and was able to get the same more golden look, if not the turquoise. But a good reminder of those controls - I had let them be set by the HST preset and figured that's the way they had to be. :lol:

I will also try out the Layer/Invert trick to see what that does and if it can be of use. I'm uncertain at the moment about green-capping in NB or even duoband, as I thought green kind of represented something in those cases.
User avatar
admin
Site Admin
Posts: 3382
Joined: Thu Dec 02, 2010 10:51 pm
Location: Melbourne
Contact:

Re: Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST

Post by admin »

Mike in Rancho wrote: Tue Aug 03, 2021 3:44 am I'm uncertain at the moment about green-capping in NB or even duoband, as I thought green kind of represented something in those cases.
Indeed, it does represent something (Hydrogen alpha in a SHO image for instance), and Cap Green should only be used as a last resort if you are certain any green is the result of a defect or noise.

The purple star trick thing is essentially turning Cap Green into Cap Purple (purple is the opposite of green).

In SHO composites, stars often tend to come up as purple, because stars emit relatively little in the Ha band (green), but much more in the S-II (red) and O-III bands (blue); combine lots of blue and red, but no green, and you end up with purple.

Some people find purple stars objectionable for aesthetic reasons. The "Highlight Repair" function in the Color module already tends to ameliorate color issues in bright highlights, so this may be all you need, without wholesale killing purple altogether through more drastic measures like a makeshift "Cap Purple" procedure.
Ivo Jager
StarTools creator and astronomy enthusiast
User avatar
admin
Site Admin
Posts: 3382
Joined: Thu Dec 02, 2010 10:51 pm
Location: Melbourne
Contact:

Re: Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST

Post by admin »

xonefs wrote: Tue Aug 03, 2021 2:28 am If there was any way to deal with halos in the wipe stage. I just have them in oiii sometimes with antlia filters, so I would think it would be ideal if there was a way to deal with them on that channel in the early stages.
Actually, you would deal with them even before Wipe - in the Compose module. If you have one band/channel that is poor in terms of detail (noisy, halos, any other defects, etc.) you can choose to use that band for just the coloring, but not the detail. Simply set the exposure length to 0 for that channel, and it will only be used for the coloring.
Ivo Jager
StarTools creator and astronomy enthusiast
xonefs
Posts: 64
Joined: Sun Jul 18, 2021 7:30 am

Re: Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST

Post by xonefs »

admin wrote: Wed Aug 04, 2021 5:55 am
xonefs wrote: Tue Aug 03, 2021 2:28 am If there was any way to deal with halos in the wipe stage. I just have them in oiii sometimes with antlia filters, so I would think it would be ideal if there was a way to deal with them on that channel in the early stages.
Actually, you would deal with them even before Wipe - in the Compose module. If you have one band/channel that is poor in terms of detail (noisy, halos, any other defects, etc.) you can choose to use that band for just the coloring, but not the detail. Simply set the exposure length to 0 for that channel, and it will only be used for the coloring.
Hmm that's interesting. More stuff/workflows to think about. Though it does seem a bit wasteful to throw away the detail from that channel if there is just one problematic halo. Last night I shot some on ic1318/butterfly, I know there will be an oiii halo on deneb, but everywhere else will be fine.

If going that route of using a channel only for color then it brings the question of planning/strategy for SHO imaging and how much integration time is needed there for just color at the expense of imaging times on channels that will contribute to detail. Typically I would try to get more time on Oiii than Ha since signal is lower, but if it is not needed for detail then I'm not sure if that is the best strategy. Ideally I want to switch filters and eliminate the halos there but in the meantime.
User avatar
admin
Site Admin
Posts: 3382
Joined: Thu Dec 02, 2010 10:51 pm
Location: Melbourne
Contact:

Re: Help getting these results starting entirely in ST? Amazing results on data started elsewhere, not so much all in ST

Post by admin »

xonefs wrote: Wed Aug 04, 2021 7:42 pm
admin wrote: Wed Aug 04, 2021 5:55 am
xonefs wrote: Tue Aug 03, 2021 2:28 am If there was any way to deal with halos in the wipe stage. I just have them in oiii sometimes with antlia filters, so I would think it would be ideal if there was a way to deal with them on that channel in the early stages.
Actually, you would deal with them even before Wipe - in the Compose module. If you have one band/channel that is poor in terms of detail (noisy, halos, any other defects, etc.) you can choose to use that band for just the coloring, but not the detail. Simply set the exposure length to 0 for that channel, and it will only be used for the coloring.
Hmm that's interesting. More stuff/workflows to think about. Though it does seem a bit wasteful to throw away the detail from that channel if there is just one problematic halo. Last night I shot some on ic1318/butterfly, I know there will be an oiii halo on deneb, but everywhere else will be fine.

If going that route of using a channel only for color then it brings the question of planning/strategy for SHO imaging and how much integration time is needed there for just color at the expense of imaging times on channels that will contribute to detail. Typically I would try to get more time on Oiii than Ha since signal is lower, but if it is not needed for detail then I'm not sure if that is the best strategy. Ideally I want to switch filters and eliminate the halos there but in the meantime.
It is, of course, possible to address halos in post through various techniques, though this may start to get into the realm - with varying degrees of severity - of "photoshopping" your image/data.

Depending on the nature of the halo, you could use the following technique;
viewtopic.php?f=4&t=2146&p=9549#p9549
halofix.jpg
halofix.jpg (70.56 KiB) Viewed 2707 times
Ivo Jager
StarTools creator and astronomy enthusiast
Post Reply