Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Ivor on Feb 21, 2013, 13:08:52

Title: First attempt at M42
Post by: Ivor on Feb 21, 2013, 13:08:52
Suprising in some ways considering the popularity of the target but this is the first time I've tried to capture this. I took the data before Christmas but processed it whilst away on business over the last couple of weeks.

I'm mixed about the final result, there are bits I'm pleased with and other sections I'm not. There's a strange vertical line of darkness to the side of NGC 1973 and I don't feel I've drawn out the white nebula well in the top right corner.

Details
Scope FLT110
Camera ST8300M
Filters RGB

20 x 60s RGB subs
Capture and stacked in AA5
Further processed  in FITS Liberator and CS4

Any suggestions on improvements welcome.

(http://farm9.staticflickr.com/8385/8494064479_1c1becaff6_o.jpg)[/url]
m42_RGB_60_SIG---org-mst-crop---bck (http://www.flickr.com/photos/runningivor/8494064479/) by running_ivor (http://www.flickr.com/people/runningivor/), on Flickr
Title: Re: First attempt at M42
Post by: RobertM on Feb 21, 2013, 18:43:45
Hi Ivor,

There's lots to like about that image, especially considering it's only 20 mins of data.  Being critical I would say you're getting a serious amount of coma which looks fairly even so a corrector should sort that out no problem.  The brighter stars have a strange Maltese cross type look to them - have you got anything impinging the light path ?

Robert
Title: Re: First attempt at M42
Post by: Ivor on Feb 21, 2013, 22:28:04
It's been such a long time since I've processed an image I forgot to get rid of the star coma, I'll have to redo that; Thanks for pointing it out.

I took these subs just before I sent by scope and camera away to be repaired the focuser was slipping and the camera had developed a fault as well so I'm not sure whether that played a part in the star spikes. I will check the all the optics are clear. Equally I didn't have the correct pacer attached to the camera hence the slightly elongated stars in the corners so maybe a combined of all of these?

I now have a replacement focuser from WO and my camera is returned tomorrow I will look to setup the kit and check for blemishes in the optics.

As these aren't new purchases I'm hoping I'll not be cursed with cloudy nights!

Title: Re: First attempt at M42
Post by: MarkS on Feb 21, 2013, 22:36:13
I'm amazed that anyone has been able to capture as much as 20 minutues of data recently!

It's looking good but to pull out more white nebula I think you'll need more data.  As Robert says, the "Maltese Crosses" indicate some very slight irregularity in the light path.

The black strip down the left hand side is almost certainly a problem with the flats you are using (or your attemptsw at background netralisation).

You've done an excellent job of handling the huge dynamic range from the bright Trapezium down to the faint wispy stuff.

Mark
Title: Re: First attempt at M42
Post by: Ivor on Feb 22, 2013, 07:14:14
Thanks Mark, I had taken 4 mins subs as well but the data wasn't up to much with the faulty kit. I'll put this on the target list again for next year again.

Title: Re: First attempt at M42
Post by: Carole on Feb 22, 2013, 08:21:37
There's an amazing amount of detail for the length and number of subs.  I particularly like the contrast of the dark nebula.  There appear to be dark rings around the stars, I would imagine this is a processing artifact. 

An excellent result on the whole for short subs on a challenging object in challenging weather conditions. 

Carole

Title: Re: First attempt at M42
Post by: Mike on Feb 22, 2013, 11:05:44
Very nice Ivor. A few flaws but they don't really detract too much from the image overall. I'd be pleased with that.
Title: Re: First attempt at M42
Post by: Ivor on Feb 22, 2013, 12:57:14
Thanks for the positive feedback.

Slowly getting there just need some fresh data!!!
Title: Re: First attempt at M42
Post by: julian on Feb 22, 2013, 14:15:20
I'd be very pleased with that image with just 20 mins of data.

julian

Title: Re: First attempt at M42
Post by: Rocket Pooch on Feb 22, 2013, 19:06:08
cooled osc
Title: Re: First attempt at M42
Post by: MarkS on Feb 23, 2013, 02:55:51
Quote from: Rocket Pooch
cooled osc

???
Title: Re: First attempt at M42
Post by: Rocket Pooch on Feb 23, 2013, 09:29:07
:-)