Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Nov 14, 2018, 23:59:26

Title: M42 - 10 years on
Post by: MarkS on Nov 14, 2018, 23:59:26
I can't believe it was fully 10 years ago that I first imaged the Orion Nebula through my Celestron C11 SCT scope.

I had some time left at the end of an imaging session a couple of weekends ago so I managed an hour of data before the clouds rolled on. Again using the C11, this time I'm using the Starizona Large Format 0.8x reducer/corrector and the modified Sony A7S.

90x30sec at ISO 10000 plus 10x30sec at ISO 1000 (for the core):

(http://www.markshelley.co.uk/Astronomy/2018/M42_20181103_45min_small.jpg)

Two stacks were done in PixInsight and a single HDR image created from the result.
Stretched using PixInsight ArcsinhStretch (of course!)
Noise reduction done using Camera Raw Filter in Photoshop.

Larger version is here:
http://www.markshelley.co.uk/Astronomy/2018/M42_20181103_45min.jpg

If you want to compare it with the version from 10 years ago, it's here:
http://www.markshelley.co.uk/Astronomy/2008/m42_2008.html

Mark
Title: Re: M42 - 10 years on
Post by: Carole on Nov 15, 2018, 08:22:04
The original version was pretty good even back then, but the new version is certainly showing more dust and detail.

I am pretty sure you have imaged M42 with your Tak Epsilon since then though, so I think I am right in saying this is a C11 10 year comparison.

It's 7 years since I imaged M42 and was thinking of doing a new version this winter too.

Carole

Title: Re: M42 - 10 years on
Post by: NoelC on Nov 16, 2018, 09:30:43
Just awesome Mark.
The original was really good this one shows so much more detal.
Wonderful processing.

Noel
Title: Re: M42 - 10 years on
Post by: RobertM on Nov 17, 2018, 17:19:12
That looks really good Mark, I especially like the smoky looking dusty detail inside the nebula.

Some of the smaller stars are showing what looks like a small blue registration artefact; other than that it looks spot on.

Robert
Title: Re: M42 - 10 years on
Post by: MarkS on Nov 21, 2018, 19:06:18
Quote from: RobertM
Some of the smaller stars are showing what looks like a small blue registration artefact; other than that it looks spot on.

It's not a registration artefact but a chromatic aberration artefact.  Unfortunately, the corrector is not perfect.  It produces sharp stars right to the edge of a full frame camera but there is definite chromatic aberration on brighter stars.  It only shows on the smaller stars in my image because I had to employ fairly sophisticated techniques to treat the larger stars.  It's the first time I've needed to separate an image into a "star layer" and a "background layer".

Mark

Title: Re: M42 - 10 years on
Post by: Hugh on Nov 22, 2018, 09:37:40
Wow Mark!  That colour looks so rich it could almost be a painting.

Hugh
Title: Re: M42 - 10 years on
Post by: ApophisAstros on Nov 22, 2018, 10:40:55
Quote from: Hugh on Nov 22, 2018, 09:37:40
Wow Mark!  That colour looks so rich it could almost be a painting.

Hugh
I suppose we are painters to a certain extent as we put blank canvas down on screen and put whatever colour we want to wherever on the image . only the structure detail is constant. That's why when you look at compatible images online each one is different by varying degrees.
Roger