HDR Merge

[Star Gazer]

I was out last night imaging M42 last night. I've had a go at M42 before but didn't create anything I was particularly proud of.

Obviously M42 can be a bit tricky since it has a high dynamic range (HDR); faint in the outermost reaches and bright in the inner core. I'm using my DSLR so I devised this imaging strategy

10x5 @ is800 + darks

10x15 @ is800 + darks

10x30 @ is800 + darks

10x60 @ is800 + darks

10x120 @ is800 + darks

10x240 @ is800 + darks

No bias or flat frames.

Please comment if you think my strategy could have been better.

My idea is to process each of the six groups above into an single image, and then merge them.

So my question is what is the best way to merge the six resultant images into the final output?

I have access to PixInsight, Nebulosity and DSS. Can any of these tools merge the six into an satisfactory result. If so how can this be done?

If you have a proven workflow using any other tool, and would like to educate me I be chuffed to hear from you.

[Psychobilly]

You could try entropy weighted average stacking in DSS but to control noise I found that ideally you needed more subs in each group...

I have used the process each group method then aligned them in CS as a layer stack with varying opacitiy for each layer...

I havent tried the auto HDR processing though... or Pixinsight...

I guess Harrys spidy senses will have him popping along soon...

Peter..

[harry page]

Hi

There is a vid on my computer , I will upload it tonight

Very very easy to do in Pixinsight

Harry the Spider

[Star Gazer]

Thanks Peter, Harry,

How many subs would you do in each group 20, 30 ..? what about darks with a 7D? again how many in each group?

I will post you the result when I have it. I think it's gonna be a beauty. May be not to you season pros, but to me it's gonna be a stunner just you see!!

..Just in case it doesn't turn out that good, I'm offer to the super market to buy me some humble pie

[Psychobilly]

Try the Entropy Weighted Average (HDR) with the files you already have.. it might work... and you have nothing to loose...

I used to try and get a min of 25 subs and use one of the Outlier rejection stacking methods (Kappa Sigma or Median Kappa Sigma) - Kappa sigma will largely take care of those pesky satellite an plane trails and to soem extent the odd passing cloud

I haven't done much long exposure noise analysis with my 7D as its supposed to be my General Photography Camera and won't be modded.. My maian astro cam was a modded 1000D...

I am not sure how well matched (temperature wise) the darks need to be with the 7D...

Peter...

[harry page]

Hi

Sorry for the delay

Here is a vid on HDR composition in Pixinsight , you will love this

http://www.harrysastroshed.com/HDR%20comp.html

Regards Harry

[Star Gazer]

Hi Harry,

Thanks for making the video available; much appreciated!!

Haven't viewed the vid properly yet as the sound card on my PC is taking some time off from normal duty. All will be well with a reboot, but can't do that as DSS is currently having a play with my subs.

Thanks again.