Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Ian on Dec 10, 2007, 15:05:30

Title: M42 from Tuesnoad
Post by: Ian on Dec 10, 2007, 15:05:30
I had a little success on Friday night. This was 20 unguided 70 second exposures. Artemis 285 and a 300mm Lens. Minimal processing, basically stacking and histogram stretching in MaximDL.

Ok, lots of histogram stretching...

(http://gallery.orpington-astronomy.org.uk/albums/userpics/10006/m42_dsc.jpg)
Title: Re: M42 from Tuesnoad
Post by: JohnP on Dec 10, 2007, 15:48:05
cool - good to see you got something - did you manage to sort out your guiding...? What happened to the Pleaides..?

John
Title: Re: M42 from Tuesnoad
Post by: Ian on Dec 10, 2007, 16:00:05
the Pleiades needs some more work...

I didn't have too much success guiding, not sure if it's software or hardware yet. Still, I think I know how to get it working...

Should have taken many more exposures of both objects. Still, I'm on the bottom end of the learning curve, but now I'm starting to get something worth looking at :)
Title: Re: M42 from Tuesnoad
Post by: Fay on Dec 10, 2007, 16:41:02
Ian I think that is very good!! So much progress from a lot of people on Friday!!!!

I would have liked to watch you guiding with Maxim
Title: Re: M42 from Tuesnoad
Post by: Mike on Dec 10, 2007, 16:53:35
Very nice Ian. You've processed it well, the trapezium area isn't burnt out.
Title: Re: M42 from Tuesnoad
Post by: Jim on Dec 10, 2007, 21:53:44
Ian, that's really lovely.  Looks like I'm spoilt for images to show at the Dec meet.
Title: Re: M42 from Tuesnoad
Post by: MarkS on Dec 11, 2007, 06:22:41

That's come out nicely Ian.
Title: Re: M42 from Tuesnoad
Post by: Mac on Dec 11, 2007, 14:22:23
nice image
Title: Re: M42 from Tuesnoad
Post by: Ian on Dec 12, 2007, 12:52:55
Thanks, all.

I didn't actually get Maxim guiding Fay, but it was not the fault of the webcam. More the fact that the mount wasn't moving in response to the guider. I have since found out that there is a strong possibility that that is because I didn't enable the guideport. D'oh!

I have a question for some of the more experienced imagers, when I'm stretching the histogram my stars get really quite bloaty. Is this a failing of my optics or processing technique do you think? I'll post my M45 shortly as a demonstration...
Title: Re: M42 from Tuesnoad
Post by: Mike on Dec 12, 2007, 13:30:25
Stars can bloat once you start to stretch the image. You can get rid of that using deconvolution, but getting the settings right is a pain in the ass. Are you sure that your focus was spot on that night and that atmospherics weren't causing them to image larger than they were?
Title: Re: M42 from Tuesnoad
Post by: JohnP on Dec 13, 2007, 10:13:43
Ian - It's really important not to saturate the whites in stars as they start to seriously bloat... I always keep a check on this in PS by using the 'colour sampler tool' Basically you place a sample point over the top of the brightest star & then when you are processing keep an eye on the saturation level using the info palette..

Hope that makes sense - I can show you how to do it if you want...

John
Title: Re: M42 from Tuesnoad
Post by: Mike on Dec 13, 2007, 10:43:29
Try a Digital Development stretch in MaximDL and then adjust the histogram and curves and see if that helps.