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Captured by
Douglas Rollain

Lion Nebula SH2-132 - RC71

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Posts Made By: Jim Thommes

March 14, 2006 05:27 AM Forum: CCD Imaging and Processing/Deep Sky

Thor's Helmet

Posted By Jim Thommes
Thanks to all of you for the kind comments.

Jim and Ivan,
I am impressed that you were able to observe this object visually. I was at a dark site when I got this data. While I was setting up and looking at the area visually, I really had to convince myself I was really seeing something.

Vincent Bert said:

Thats awesome Jim! I'm really impressed that you didnt spend much time getting data. Man, I'd have shot that object for 6 hours and still not gotten as good a result. So whats the secret with that chip youre using?

So, I did shoot at a fairly favorable focal ratio, but the Artemis camera concept is optimized for low noise. The trade off is more processing during the download - it takes about 14 sec for a full frame (1x1) download of only 1392x1040 pixels. Its OK with me, I'll wait, it just means I can stretch a little more before the noise becomes objectionable.

March 15, 2006 05:47 AM Forum: CCD Imaging and Processing/Deep Sky

NGC 4565 - LRGB

Posted By Jim Thommes
Vince,
Really nice image. The color overall seems very good - I don't mind a little blue around the hot stars. (I've gotten quite used to seeing it with my equip).

You mention considering a minus violet - I have used a IR/UV cut with my RGB's - not exactly the same but I do see less FWHM on the blue with it. Also, I thought that some blue haloing came from atmospheric dispersion as well. If so, I guess nothing you do with optics would reduce FWHM beyond some limiting value.

Of course you could always shoot in poor seeing - its a great equalizer if you don't mind all your stars the size of small planetaries.

Warren is right, PS can be set up for effective blue halo reduction.



March 26, 2006 07:30 PM Forum: CCD Imaging and Processing/Deep Sky

NGC 7331

Posted By Jim Thommes
Dan,
Nice Image. I like the color you got overall in the field - particularly the fainter stars. I seem to loose color to a neutral gray/white on fainter stars. I know my process tends to do this since I clip low intensity color because I want to eliminate color artifacts.

So what made you want to reprocess (other than those pesky clouds)? Did you apply some new techniques?

March 26, 2006 07:42 PM Forum: CCD Imaging and Processing/Deep Sky

M81 - Finally, a clear night!

Posted By Jim Thommes
Tyler,
Yeah, Seems like clear nights have been hard to come by so far in 2006. Your M81 came out great given the seeing and light pollution, you must have done everything else perfect to have such a fine image.

I do like the second image better - it brings out more detail. Smoothing may have been a bit heavy - although that could just be the effects of seeing. I know what you mean about noise reduction though and how much to apply - it is so easy to do too much. I am guilty of this often.

March 28, 2006 04:36 AM Forum: CCD Imaging and Processing/Deep Sky

M51 Luminance Data - from Utah

Posted By Jim Thommes
Tyler,
Cool image - great capture. I hope you can get the color soon - I'd be interested to see that.

It could just be my monitor, but I think you could curve up the luminance to brighten the object and bring out more detail. When I did this on my monitor, I saw a lot more detail in your image.

April 2, 2006 10:05 PM Forum: CCD Imaging and Processing/Deep Sky

M106 Core - Luminance

Posted By Jim Thommes
Tyler,
Seems like both you and Cal got some good luminance captures - Congrats to both of you.

I still think you leave some object detail on the table so to speak. Seems like you are processing to gamma standard less than what might be considered typical. (Although I conceed, my monitor may be a bit on the dark side.)

I look forward to seeing the color version from both you and Cal - here's hoping for some clear skies.

April 2, 2006 10:19 PM Forum: CCD Imaging and Processing/Deep Sky

M63 The Sunflower Galaxy - from Utah

Posted By Jim Thommes
Nice M63 Tyler. I see you also got PGC45992 in the lower right corner.

April 4, 2006 04:39 AM Forum: CCD Imaging and Processing/Deep Sky

Clusters NGC2362 and NGC2420

Posted By Jim Thommes
Thanks for the comments guys. I liked getting the fuzzies in NGC2420 - didn't expect them when I planned the image. But its kinda fun to see them come up on the sub downloads when you're not expecting them.

April 10, 2006 01:07 AM Forum: CCD Imaging and Processing/Deep Sky

Centaurus A

Posted By Jim Thommes
Greg,
Nice Shot. I have so much wanted to do this object, but it is pretty low in my Southern skies. Thans for sharing.

April 10, 2006 01:18 AM Forum: CCD Imaging and Processing/Deep Sky

The Whirlpool

Posted By Jim Thommes
Nice Shot Dan. I like the colors you got in the dust lanes. I am curious, you are shooting in some light pollution as you say, how did you divide the 8.8 hrs of luminance? Many shorter subs? I know this was a mix of old and new data, but in general, how many subs is the 8.8 hours?

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