M20, Help please

[desler]

Hi again,


Strange last night, after M83 I turned my attention to the Trifid neb.

Capture 15 x 4 min exp, iso 1600 icnr off through my ed80 and eos 1000d. guided with phd.
Darks, Flats and bias frames applied.

The subs looked great on the laptop, Processing in either photoshop or gimp, I don't seem to be able to bring much detail out and I can see some dark artifacts in the neb.

My question is: Did I introduce the artifacts or muck up the capture or
anything else you may think of!

Thanking any and all in advance.

Darren

[RobF]

Hope you don't mind me playing Darren.
Fiddled with masking stars and colours to help stretch out a bit more here and there. Many of the dark patches you have captured are real dark nebulosities I think you'll find if you look at a "super duper" image.

Mind you, I do have a tendancy to let my blues get out of control sometimes....!:whistle:
Anyway, looks to me like you've got quite a bit more detail in your subs that could be teased out. Nice work - definitely couldn't be classed as "mucked up!"

[desler]

Thanks Rob,


I don't mind anyone editing my posts of playing around with the pics!
It's all a learning curve, and learn I must!

Processing is a whole other world and one I sometimes end up happy with, at others; not so.

As others have also said, I think processing and assessing your own work is better after a few hours sleep.

Thanks again.

Darren

[dannat]

Can i say I have the same trouble Darren,

RobF - can you give us two things that you did please to bring out the Neb, your processing has really bought out the neb

[Alchemy]

2 quick tips

1. check your work against others, this will help in confirming whether its real or not (artifacts/detail)

2. match the darks to your lights (temp) to within a degree or two at most

you may already do this, but its useful to do.

[RobF]

Most of it was done with selective color ranges in PS. I'm only just starting to play with the possibilities this creates after reading some great tuts that Peter posted: http://www.iceinspace.com.au/forum/showthread.php?t=42216
Definitely some good stuff in there. Up until now I used to restrict myself to playing with Curves and Levels, but I'd love to really understand and use layers and selective ranges.

I can't recall exact order I applied, but something like:
Select/Color Range..../drop box choose "Shadows" - click invert (effectively selecting starts and bright neb)
Select/Grow (take in a bit more of the faint neb)
Then use Curves and Levels to brighten.

I repeated this lightly for just the blues too:
Select/Deselect
Select/Color Range..../drop box choose "sampled colors" - then click on the faint blue bits of neb
Select/Modify/Expand.... (large enough to get the blue bits of interest)
Then Curves/Levels to brighten.

I'm assuming you've already got your head around non-linear stretches using Curves, and tweaking black points with Levels - if not, perhaps check out:
http://www.ezystyles.com.au/photoshop.html

You can also use selective ranges to just work on the background (less stars etc) and pull down some noise etc - should be more on that in the original tuts I mentioned. Noise can become an issue as you enhance colours and details - but that's a whole new area to play in.

And last but not least - remember to keep an eye on the clock..... :)

[dannat]

thanks for the tips Rob, much appreciated

[desler]

Thanks Rob,

Sorry for the tardy reply, but back at work now, so don't get so much time to sit and ponder and browse.

Darren