#1  
Old 10-01-2018, 08:08 PM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
Ngc3324

Ngc3324 narrowband first attempt never took narrowband before
not sure what to do help would be great for feedback
took HA Lum + Red O111 for green S11 for blue
I Redone the second image SII to RED HA GREEN O111 BLUE does it look better is this right.
Do I take RGB as well to layer with narrowband not sure.
Martin
Attached Thumbnails
Click for full-size image (NGC3324 1.jpg)
214.5 KB105 views
Click for full-size image (ngc 3324.jpg)
185.1 KB39 views

Last edited by willik; 11-01-2018 at 11:42 AM.
Reply With Quote
  #2  
Old 10-01-2018, 09:24 PM
Rigel003's Avatar
Rigel003 (Graeme)
Registered User

Rigel003 is offline
 
Join Date: May 2006
Location: Adelaide, South Australia
Posts: 1,079
It's extraordinarily beautiful just as it is. Great image!
Reply With Quote
  #3  
Old 10-01-2018, 09:58 PM
Placidus (Mike and Trish)
Narrowing the band

Placidus is offline
 
Join Date: Mar 2011
Location: Euchareena, NSW
Posts: 3,719
Congratulations on your first narrowband. You'll never look back.

You can of course legitimately map any filter to any channel, and if you are just using two filters (H-alpha and OIII) people often elect to go for a "natural" look by mapping the H-alpha to red, faking in a bit of blue for H-beta even though they didn't actually photograph it, and mapping OIII to cyan.

With three filters, as in your case, one can still map anything to anything, but aiming for a "natural" look is totally inappropriate because H-alpha and SII are in nature both almost exactly the same colour and you would be wasting your time.

Traditional with a three filter image, (like driving on the left) is to map SII to red, H-alpha to green, and OIII to blue.

Because there is usually much less SII emission up there than H-alpha, if one gave equal emphasis to each filter, the resulting image would be overwhelmingly green, with only a hint of blue from the OIII and negligible red from the SII.

Therefore, for very good and proper reasons, one usually has to greatly increase the brightness of the SII, and somewhat increase the brightness of the OIII, relative to the H-alpha in order to be able to see them clearly.

Using H-alpha as a luminance channel has its advocates, but it is not a good idea for objects where the topical distribution of H-alpha and OIII are almost mutually exclusive. There are many examples in the Magellanic Clouds. Personally I'd not recommend getting into the habit of using H-alpha as a luminance channel, as it will actually suppress the OIII in such regions.

There are two places where adding RGB can be of use. One is in reflection nebulas, which are usually broadband blue, so only a tiny bit of it gets through narrowband filters. That certainly doesn't apply to Gabriela Mistral.

The other is for adding RGB stars. This is purely cosmetic. One uses a star mask, so as to take the nebulosity from the narrowband, and the stars from the RGB.

An alternative to that is to use your star mask to take the stars from the H-alpha channel, but mapped to white. Both methods (RGB stars or H-alpha stars mapped to white) avoid getting highly distracting magenta haloes around the stars.

Once again well done. Lovely composition. Instantly recognizable, and very successful.

Very best,
Mike
Reply With Quote
  #4  
Old 10-01-2018, 10:23 PM
strongmanmike's Avatar
strongmanmike (Michael)
Highest Observatory in Oz

strongmanmike is offline
 
Join Date: May 2006
Location: Canberra
Posts: 17,150
Nice first NB image Willik and...what Mike said

Mike
Reply With Quote
  #5  
Old 10-01-2018, 11:26 PM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
Thanks Michael and Trish for your very helpful feedback that is a great help
thanks Graeme and Michael
Martin
Reply With Quote
  #6  
Old 11-01-2018, 11:48 AM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
I Redone the image added a second image
does it look better SII TO RED HA TO GRREN O111 TO BLUE
Martin
Reply With Quote
  #7  
Old 11-01-2018, 02:11 PM
RickS's Avatar
RickS (Rick)
PI cult recruiter

RickS is offline
 
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
I like both. Martin! Good advice from M&T. Only one thing I'd add: take a look at J.P. Metsavainio's tone mapping technique:

https://astroanarchy.blogspot.com.au...e-mapping.html

I don't use the whole process but I do use the core idea of removing the stars when processing NB colour data.

Cheers,
Rick.
Reply With Quote
  #8  
Old 11-01-2018, 04:57 PM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
Thanks Rick for your help
Martin
Reply With Quote
  #9  
Old 12-01-2018, 10:38 PM
Ross G
Registered User

Ross G is offline
 
Join Date: Apr 2007
Location: Cherrybrook, NSW
Posts: 5,006
Great looking photo Martin....and only your first attempt!

Good luck on this new path.

I am close to my first attempt so seeing work like yours is encouraging.

Ross.
Reply With Quote
  #10  
Old 13-01-2018, 12:31 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Beautiful fov. Nice colours. Stars are a bit burnt by easy to fix then you'll have one for the poolroom.
Reply With Quote
  #11  
Old 14-01-2018, 11:18 AM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
Thanks Ross thanks Marc for your feedback narrow band first attempt
another learning curve.
Martin
Reply With Quote
  #12  
Old 17-01-2018, 08:09 PM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
You've gone pretty deep there Martin and you've achieved quote a nice contrasty result
Reply With Quote
  #13  
Old 18-01-2018, 01:34 AM
willik (Willik)
Registered User

willik is offline
 
Join Date: Nov 2009
Location: Perth WA
Posts: 715
Thanks Atmos for your comment nice to get a image that looks good
Martin
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 05:16 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement