Auto star shrink

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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arrowspace90
Posts: 28
Joined: Mon Jul 13, 2020 6:59 pm

Auto star shrink

Post by arrowspace90 »

If I try to use the auto shrink for stars in this RGB image, will the mask protect the background elements of the galaxy, or will the stars in M33
be shrunk as well?
Obviously I don't wish the latter, so would I need to manually pick stars to shrink to be safe? The large yellow ones are the main culprits when seen at a higher resolution and there aren't all that many of them.
Attachments
Capture M33.jpg
Capture M33.jpg (64.08 KiB) Viewed 629 times
happy-kat
Posts: 271
Joined: Sun Feb 01, 2015 11:31 am

Re: Auto star shrink

Post by happy-kat »

You create the mask you want on the stars you want, you have the control
arrowspace90
Posts: 28
Joined: Mon Jul 13, 2020 6:59 pm

Re: Auto star shrink

Post by arrowspace90 »

right. I don't know how to do that.
arrowspace90
Posts: 28
Joined: Mon Jul 13, 2020 6:59 pm

Re: Auto star shrink

Post by arrowspace90 »

In the example below, I just want to shrink some of the bright, bloated stars.
But when I try the auto method, the galaxies in the group are green along with the stars.
I have tried several times with a lasso mask to circle the problem stars, or to circle the galaxies. But I can't figure out
how to tell Star Tools to shrink ONLY the stars and leave out the little galaxies.
Can someone tell me simply what the steps are?
Yes, I stipulate I am dumb to not know how to do this.
Attachments
M77 group.jpg
M77 group.jpg (55.42 KiB) Viewed 122 times
arrowspace90
Posts: 28
Joined: Mon Jul 13, 2020 6:59 pm

Re: Auto star shrink

Post by arrowspace90 »

So here, I have got masks over mostly just the stars I want to shrink with the little galaxies excluded. Looks like it would work but...

what do I do now? If I press the obvious "shrink" tab, the green masks shrink, not the stars. So this is where I am stuck. I could do this backwards, and
just mask the galaxies, perhaps that's more correct. But then, same thing, how do you execute the shrink to actually happen?
Attachments
M77 star mask.jpg
M77 star mask.jpg (55.22 KiB) Viewed 115 times
almcl
Posts: 178
Joined: Wed Jan 21, 2015 7:15 pm
Location: Shropshire. UK

Re: Auto star shrink

Post by almcl »

Don't use the 'Shrink' button within the mask module - that's for changing the size of the mask.

To change the size of the stars, having created your mask, 'Keep' it and then, when back on the main page, select the Shrink button there:
shrink.jpg
shrink.jpg (24.33 KiB) Viewed 103 times
Here's what I got when operating on your image above, not perfect by any means, but have a play with the iterations and other parameters in the Shrink module:
Untitled-1.jpg
Untitled-1.jpg (57.27 KiB) Viewed 102 times
Skywatcher 190MN, astro modded Canon 700d, cls ccd, or Ha or Oiii filters, guided by OAG, ASI120, PHD2
arrowspace90
Posts: 28
Joined: Mon Jul 13, 2020 6:59 pm

Re: Auto star shrink

Post by arrowspace90 »

Thanks.
Of course I was using the "Shrink" tab. I didn't try iterations, so I will do that. What you did is an improvement. I read that SCTs and RASAs like mine are prone to bloated stars and halos.
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