M16

[Omaroo (Chris Malikoff)]

Hmm... star reconstruction is fun

EDIT: Stacking abberation? (see circled area)

[gregbradley]

Good to see the RCOS performing well. Nice round stars too.

I did not know an STL6303 would bloom stars - isn't it an antiblooming chip? If so perhaps you need to set the antiblooming setting. I believe they are adjustable on an STL camera.

The Ha blend has given you a salmon pinkish colour which is the result of combining Ha with LRGB as another layer?

Rob Gendler has some techniques about blending Ha on his website.

Others have generated their own approach. It is worth working out a method for blending in Ha with LRGB otherwise the dreaded salmon colour
is the result. Ideally your Ha combination technique produces nice deep red shades of colour without red speckles in the background and without wrecking star colours! Phew. Not asking much eh? Also it can be used to enhance detail and showing the presence of background hydrogen gas which always seem to be present around emission nebulae.

Greg.

[lhansen (Lars)]

Hi Greg

The AP reducer at F6.75 lets me image in conditions that the full F9 would not.

The STL6303E is not anti blooming. There is an anti blooming version available but it knocks the sensitivity to hell. I think there is some form of AB adjustment for the camera but I have not chased it to ground yet.

I've got a copy of Robs techniques for Ha and in fact for the M16 image I used his technique for a luminance combine using PS. I've still got heaps to learn in this space . For the M20 image I combined the Ha and Red channels which creates some interesting effects.

aint life grand

Cheers

Lars

Originally Posted by gregbradley

Good to see the RCOS performing well. Nice round stars too.

I did not know an STL6303 would bloom stars - isn't it an antiblooming chip? If so perhaps you need to set the antiblooming setting. I believe they are adjustable on an STL camera.

The Ha blend has given you a salmon pinkish colour which is the result of combining Ha with LRGB as another layer?

Rob Gendler has some techniques about blending Ha on his website.

Others have generated their own approach. It is worth working out a method for blending in Ha with LRGB otherwise the dreaded salmon colour
is the result. Ideally your Ha combination technique produces nice deep red shades of colour without red speckles in the background and without wrecking star colours! Phew. Not asking much eh? Also it can be used to enhance detail and showing the presence of background hydrogen gas which always seem to be present around emission nebulae.

Greg.

[gregbradley]

Hi Lars,

I have heard of a setting for the STL11. I am assuming there is a similar setting for the 6303 but then the STL11 is antiblooming.

The reducer is a good thing expecially with your 6303 sized chip.
F9 can be time consuming for imaging.

Although it won't work on an 11000 chip or above as its corrected circle is too small.

One method for Ha combining is outlined in Wodaski's Zone System book by Russell Croman. It is assigning Ha to a layer on top of your finished LRGB image. Select lighten as the mode. You can adjust the opacity slider to suit how strong an effect it makes. Or try experimenting with the other blending methods.

it works reasonably well and is easy to do.

I find Screen mode works better if toned down.
I find it is good to run a noise reducing technique on the Ha before trying to blend it. Also use curves/levels on the Ha layer to reduce the red stars (use lasso if needed). You want the nebula to be red enhanced not the stars.


Greg.

[Omaroo (Chris Malikoff)]

And the second iteration here now as well. I spent quite a bit of time doing a pixel-level 50% strength blur at 500% zoom with a 9px fuzzy brush. I masked the stars first so they'd keep tighter focus and dodged around those that weren't masked. Looks better I think.

Flick between them and the difference is pretty apparent.