#1  
Old 17-09-2020, 11:34 AM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 888
How does everyone combine Ha into RGB?

Hi All,
For the most part I have been combining my Ha data into RGB via pixelmath: (Ha*0.5)+(R*0.5), however lately I feel this is not the best way to do it - it seems to squash the natural colours while not really bringing out the detail that is expected in Ha. Would anyone care to share their methods of combining Ha into LRGB?
Cheers,
Logan
Reply With Quote
  #2  
Old 17-09-2020, 11:50 AM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 5,950
I could explain how to do it in Photoshop CC.
Reply With Quote
  #3  
Old 17-09-2020, 11:59 AM
Nikolas's Avatar
Nikolas (Nik)
Dazed and confused

Nikolas is offline
 
Join Date: May 2012
Location: Melbourne
Posts: 1,753
In Photoshop you add HA as a luminance layer then vary the opacity
Reply With Quote
  #4  
Old 17-09-2020, 12:46 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,858
Although it does depend on the data and object a bit as to whether I do it during the linear stage or not but usually I'll stretch both the RGB and Ha data separately, get their histograms similar and then run in PixelMath R*R+Ha*(1-R) on the red channel.

What this does is keep the brighter regions mostly R (especially for stars) but the fainter regions become more and more Ha dominant. This particular expression doesn't work while in linear, sometimes I'll do a LinearFit on Ha using R as a reference and then use the Max(R,Ha) expression which just takes the brighter nebulosity of Ha and adds it into the R. It isn't always as neat though as it sometimes doesn't make the stars look that nice; they like they don't match the nebulosity.
Reply With Quote
  #5  
Old 21-09-2020, 10:15 AM
Andy01's Avatar
Andy01 (Andy)
My God it's full of stars

Andy01 is offline
 
Join Date: Mar 2012
Location: Melbourne
Posts: 2,668
Marco Method...

Logan, look no further - THIS is the business
Reply With Quote
  #6  
Old 21-09-2020, 11:01 AM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 888
Quote:
Originally Posted by Andy01 View Post
Logan, look no further - THIS is the business

Thanks Andy!! Looks to be quite useful! Only thing is, it doesn't seem to bring out any dust/detail that you would normally associate with Ha signal? Or is that intentional?
Reply With Quote
  #7  
Old 21-09-2020, 11:02 AM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 888
Quote:
Originally Posted by Atmos View Post
Although it does depend on the data and object a bit as to whether I do it during the linear stage or not but usually I'll stretch both the RGB and Ha data separately, get their histograms similar and then run in PixelMath R*R+Ha*(1-R) on the red channel.

What this does is keep the brighter regions mostly R (especially for stars) but the fainter regions become more and more Ha dominant. This particular expression doesn't work while in linear, sometimes I'll do a LinearFit on Ha using R as a reference and then use the Max(R,Ha) expression which just takes the brighter nebulosity of Ha and adds it into the R. It isn't always as neat though as it sometimes doesn't make the stars look that nice; they like they don't match the nebulosity.

Thanks Colin - That seems really useful especially for bringing out the faint dust. Maybe a combination of these two (Marco and this) methods could be interesting... Props for a pixinsight only combination
Reply With Quote
  #8  
Old 21-09-2020, 03:46 PM
LewisM's Avatar
LewisM
Novichok test rabbit

LewisM is offline
 
Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 9,940
I know it's a PS routine, but Starizona has 2 good methods. It's basically the same as Marco's too, and considering how delightful Marco's images are, I'd be paying attention. PI doesn't do everything perfectly.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 02:02 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
Limpet Controller
Advertisement
Astronomy and Electronics Centre
Advertisement