Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_30_second_exp_2_winners.thumb.jpg.b5430b40547c40d344fd4493776ab99f.jpg

gnomus

Pickering's Triangle - Additional 3 hours 20 mins

Recommended Posts

Using Channel Combination (just as you do for RGB).  Leave it in RGB combination.  Put Ha in for Red, OIII in for Green and Blue - click the circle.  I do this before stretching (whilst still linear), which is what I do for 'normal' RGB combinations and so I assume is correct.

Share this post


Link to post
Share on other sites
2 hours ago, ollypenrice said:

I don't do 'NB only' images but do combine Ha and OIII with RGB ad LRGB. A system I use might be of interest, though. It's all to do with how much of which filter to map to which channel. In Ps you can build up a system of layers, a stack of different mappings using layers, and then vary the opacity of each to see, in real time, the effects of the blends. So you might, for instance, in the 'RGB' channels stack something like:

Ha, (blend mode luminance)

Ha OIII OIII (blend mode normal)

Ha OIII Ha (justifiable on the grounds that H beta, which is blue, traces the same gasses as Ha.) Blend mode normal.

The opacity slider would then give you a real time blend.

If you NB types are already dong this then I'll slink away with apologies...

Olly

Olly.  If I got some RGB of Pickering could I combine this using your method with my NB data, and would it look similar to my HOO only image, but with 'proper' star colour?

Edited by gnomus

Share this post


Link to post
Share on other sites
9 hours ago, gnomus said:

Olly.  If I got some RGB of Pickering could I combine this using your method with my NB data, and would it look similar to my HOO only image, but with 'proper' star colour?

You could, and it would be similar. It should work well. In fact there is strong blue signal which may be reflection rather than simply OIII and H beta (which a blue filter will pass) so you might have RGB, particularly B, adding to the nebulosity as well as the stars. The nice trick we worked out with the Seagull was making the three layer stack

G-OIII B

RG B-OIII 

Ha-R GB

...so as to be able to weight the OIII balance between green and blue.

Ha as luminance needs to be handled with great care and applied sparingly over RGB. It risks diluting the red colour, subduing the green and blue and giving blue star halo artefacts.

Olly

  • Like 1

Share this post


Link to post
Share on other sites

Thanks again Olly.  I may give that a go at some point - but I'm knee-deep in the Pacman at the moment.

Share this post


Link to post
Share on other sites

In Pixinsight Channel Combination it says no compatible files.

I have my Ha and OIII files open in pixinsight they are .xisf extension

Share this post


Link to post
Share on other sites

That is odd.  Have you star aligned and dynamic cropped them?  (You know you can apply the same dynamic crop to aligned images, don't you?).  If you want to Dropbox them I can have a go later if you like.

Share this post


Link to post
Share on other sites

The only other thing I can think of is to ensure that RGB is selected.  Mine looks like this:

ChannelComb.jpg

Edited by gnomus

Share this post


Link to post
Share on other sites

I had cfa images checked in the batch processing menu as the last run I did with a DSLR camera.

I unchecked it and did my batch processing again and all is well.

Thanks.

Share this post


Link to post
Share on other sites

Thanks all for the encouragement.  I got notification today that 'Astronomy Now' are going to publish the picture.

  • Like 2

Share this post


Link to post
Share on other sites

I have returned to this thread countless times to admire this image, just stunning !

  • Like 1

Share this post


Link to post
Share on other sites

Well I must say that image sinks into my eyes like a velvet smooth optical whisky, it is simply stunning!
Cheers
Will

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.