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Captured by
Lawrence Parchman

Sculptor Galaxy (NGC 253)

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Posts Made By: dan kowall

April 10, 2009 03:27 PM Forum: CCD Imaging and Processing/Deep Sky

Just picked up an ST-10XME CFW8a+LRGB Ha

Posted By dan kowall
You'll love the high QE on the ST-10, Jeff.
Don't worry about the blooming, it's not that hard to fix.
I don't know what processing program you're using but if you have CCDStack or Photoshop the principles are the same.
If your blooms are small, you can get away with 'imputing' information from surrounding pixels to fill in.
When blooms are large, I like to take an extra set of short exposures where there's no blooming. Layer the two masters together and set the blooms to 'transparent' (in CCDStack) or use a mask (in Photoshop).
The data from the short exposure master can also be used to provide star color to saturated stars in the long exposure master.

dan

April 11, 2009 01:35 PM Forum: CCD Imaging and Processing/Deep Sky

Gum 17 in Vela

Posted By dan kowall
Nicely imaged, Louie.
There are lots of objects to mine in Vela.
I remember a wide field view of Vela that Johannes Schedler did and it was populated with all kinds of interesting stuff.
Will you be doing more images in this area?

dan

April 11, 2009 03:38 PM Forum: Astro-Physics

Cleaning a dirty lens (was how reflective)

Posted By dan kowall
Does anyone have a source for Balzer's Substrate Cleaner #2?
My searches have come up empty.

dan

April 22, 2009 03:07 PM Forum: CCD Imaging and Processing/Deep Sky

Mercury against rich star fields, Dust, Gas Movie

Posted By dan kowall
That gets a thumbs-up recommendation from this reviewer.

dan

April 30, 2009 06:37 PM Forum: CCD Imaging and Processing/Deep Sky

M101

Posted By dan kowall
That's pretty cool.
I hope that you made two of those scopes and kept one for yourself.

dan

May 10, 2009 02:11 PM Forum: CCD Imaging and Processing/Solar System

Europa occulting Ganymede, 8th May

Posted By dan kowall
That's a first for me, too, Anthony.
It was well planned and executed on your part.
So cool.

dan

May 11, 2009 10:08 PM Forum: CCD Imaging and Processing/Deep Sky

Rho Ophi Complex

Posted By dan kowall
That is excellent, Jim, one of your best images.
Your color is superb and the details are fine.
My congratulations.
My only quibble, and it's a small one, is your spelling in this post. I think it should be "Rho Ophi Complex".
My best regards,

dan

May 18, 2009 09:18 PM Forum: CCD Imaging and Processing/Solar System

Ganymede-Europa eclipse animation and images

Posted By dan kowall
Hi Paul,
That's pretty cool.
I did a quick remake of your gif to minimize the "hopping around".
It appears that I reversed the temporal order of the animation, but I'm too lazy to go back and change it now.
http://members.cox.net/my_astro_images/G-E,redo.gif
Good job on your part.

dan

May 24, 2009 02:36 PM Forum: CCD Imaging and Processing/Deep Sky

M51 final?

Posted By dan kowall
Hi Charlie,
Some thoughts from the peanut gallery are below:

Charles Hakes said:

I am still spending too much time processing, so I should at least ask for feedback along the way. At least processing is something to do during all the recent rain. This may be the end of this M51 for a while, depending on your feedback to the following processing choices...

Fewer color subs - This version removed the "moon" RGB subs, and that appears to have fixed the weird gradients that I couldn't quite deal with in software. Still have 35 minutes each.
[COLOR="Teal"]*** I would gather more exposures before processing. Processing is much easier with better data. My hard drive is littered with objects that were abandoned in mid-processing because I realized that there was just not enough data to be able to produce a decent image.[/COLOR]
More contrast - Rather than continuing to fumble with curves, I just cranked the contrast slider over more than I normally would. Looking at other on-line shots, the ones with higher contrast seem to "jump out" more. Is this too much?
[COLOR="Teal"]*** Keep fumbling. A juggler doesn't start out by never dropping something. They fumble and drop, but, with practice, they learn how to do it. A contrast slider is a harsh adjustment. Most accomplished imagers never touch it, preferring the gentler and more selective curves.[/COLOR]
More sharpening - Again, more than I think looks "natural," but the result pops a bit more. Several iterations of unsharp mask here. I tried to be selective with stars, but I am sure I need more practice with that. Too much? (I have yet to do a "de-convolution" I like.)
[COLOR="Teal"]*** Yes, it's over the top as evidenced by the mottling in the blue and red channels and the stars with 'panda eyes' (especially in the red). Those artifacts are both signs of overagressive sharpening. Sharpening techniques work well on good data, i.e. with a strong S/N.[/COLOR]

More saturation - Once again more color than I personally like, but showing this to a few non-astro people, they like the vivid colors better. Again, too much?
[COLOR="Teal"]*** Yes, again too much. Trust your own judgement more. Pushing the saturation into cartoon-like effects doesn't do justice to your data.[/COLOR]

Smoother background - With a Carboni action. I think it removes some of the faint background galaxies, but is the smoothness more visually pleasing?
[COLOR="Teal"]*** I know it's easy to just run a Carboni action, but I feel that you would be better served by learning how to do the 'action' on your own. Not only would you have greater control of what's going on, but you would be learning more about processing and PhotoShop in the process.[/COLOR]

Any comments and suggestions would be appreciated. [/quote]
See what happens when you ask for comments. Be assured that they are given in a spirit of helping.
Simply stated, I think that a gentler hand in processing and more data will do your images a world of good.
My regards,

dan

June 3, 2009 03:55 PM Forum: CCD Imaging and Processing/Deep Sky

Noise Ninja

Posted By dan kowall
Hello Francois,
What version of PhotoShop do you have?
CS4 has a nice noise reduction filter. You might want to consider an upgrade instead of Ninja.

dan

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