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Captured by
Douglas Rollain

Lion Nebula SH2-132 - RC71

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Posts Made By: Jim Thommes

June 5, 2008 04:14 AM Forum: Digital SLR AstroPhotography

M8 & M20

Posted By Jim Thommes
Nice one Peter.

Is that 350 D a modified Cam?

June 6, 2008 04:33 AM Forum: CCD Imaging and Processing/Deep Sky

Flat Field & Reducing Advice

Posted By Jim Thommes
Steve,
I'm not sure how a C11 compares with a C8 like I use, But I have used the Celestron 0.63 reducer with the minimum camera distance - works out to be about f/7.5. I am using a Canon 350D (22 mm CMOS width). Here are a few images I have done recently. Likely with an SCT you will suffer from some coma / flatness issues.

http://jthommes.com/Astro/DSLR/m3.htm

http://jthommes.com/Astro/DSLR/m13.htm

These images did have a central gradient removal performed - but I did not use flats.

Ideally, on flats I have done, I like to get the average level at about half well depth or for 16 bits , 32767 ADU. I suspect an average +/- 10,000 ADU from there will probably be OK. Don't let any of your pixels get near zero. Division by a very small number causes the blowout.

June 6, 2008 04:34 AM Forum: CCD Imaging and Processing/Deep Sky

Helix Nebula

Posted By Jim Thommes
Greg,
Very nice. Well done.


June 6, 2008 04:37 AM Forum: CCD Imaging and Processing/Deep Sky

M 57

Posted By Jim Thommes
Very Nice Dietmar. I do like the capture of the outer ring feature.

June 6, 2008 04:38 AM Forum: CCD Imaging and Processing/Deep Sky

M16 HOO narrowband

Posted By Jim Thommes
Very nice Anjal.

June 9, 2008 02:30 AM Forum: CCD Imaging and Processing/Deep Sky

M3 reprocessed, need your comments please

Posted By Jim Thommes
Floyd,
Color looks real good to me - Nice image.


June 9, 2008 03:04 AM Forum: CCD Imaging and Processing/Deep Sky

M8, 17 & 27 with Orion Starshoot

Posted By Jim Thommes
Great images Ivan. I like what you are doing with the Starshoot.


June 9, 2008 03:09 AM Forum: CCD Imaging and Processing/Deep Sky

M57 LLRRGB

Posted By Jim Thommes
Sweet image Dietmar. I like the way that you blended everything - it looks very natural. I think the 2x2 bin on the Ha is a smart choice. I have recently gathered data on this target - a 1x1 choice on the Ha would be some very long exposures indeed.

June 9, 2008 03:15 AM Forum: CCD Imaging and Processing/Deep Sky

M16 Ha

Posted By Jim Thommes
Nice one Jason. From the image result, looks like you shot in pristine skies.

June 14, 2008 04:24 AM Forum: Digital SLR AstroPhotography

Widefield M27

Posted By Jim Thommes
Real nice Peter. Great job.

I wonder why we don't run into each other at the Lagunas?


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