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Captured by
Lawrence Parchman

Sculptor Galaxy (NGC 253)

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Posts Made By: dan kowall

May 28, 2007 02:03 PM Forum: CCD Imaging and Processing/Deep Sky

ngc 6207...who`s that ?

Posted By dan kowall
I've never seen such detail in 6207. It's always just a smudge in my images.
Good job, Dietmar.

dan

June 3, 2007 08:48 PM Forum: CCD Imaging and Processing/Deep Sky

M53 and NGC 5053

Posted By dan kowall
Wonderful cluster shots as always, Jim.
I especially like the widefield-two for the price of one.
My regards,

dan

June 4, 2007 04:28 PM Forum: CCD Imaging and Processing/Deep Sky

NGC 6820/23 in Ha

Posted By dan kowall
In response:
John Maher asked "Did they discover it with film. I could not see someone finding that with the naked eye."
***Some guy named Albert Marth discovered it using a 48" reflector in 1864, several decades before film became a useful tool in astronomy. It must be a wonderful visual experience to have a 48" scope and dark skies.

Warren, your crop does indeed look like a rabbit. This anonymous area could use a nickanme.

Greg Bradley asked "How do you frame your shot with such a dim object? Did the outline of it show enough in a short exposure to know it was centred in the image?"
***At a 9x9 bin in luminance, I could take a test exposure long enough to make out the outline of the 'elephant trunk', but the go to accuracy of the mount from night to night was good enough that I didn't need any centering corrections. The outlying nebulosity wasn't revealed until I processed the data.

June 5, 2007 02:17 PM Forum: CCD Imaging and Processing/Deep Sky

NGC 6820/23 in Ha

Posted By dan kowall
Thanks for all of the comments, guys.
As always, they're much appreciated.

dan

June 5, 2007 02:37 PM Forum: Equipment Talk

Shaft coupler for Robofocus

Posted By dan kowall
Hi Bob,
Look up McMaster-Carr part #: 9132k11
It's under miniature slip clutches, page 993.
When you want to disengage the RoboFocus, you just turn the clutch.
You lose the 'Home' position for the focus travel when you do this, so you'll probably want to recalibrate it every so often so you don't get into trouble.
Here's a blurry image of this clutch:
http://members.cox.net/dakoan/Jenkins%20bracket,2.jpg
I hope this helps,

dan kowall

June 10, 2007 02:04 PM Forum: CCD Imaging and Processing/Deep Sky

M20&M21

Posted By dan kowall
It looks like you're having a lot of fun with that ZS 66, Louie.
Clear skies seem to be favoring you, too.
Well done on all counts,

dan

June 11, 2007 02:22 PM Forum: CCD Imaging and Processing/Deep Sky

M13

Posted By dan kowall
NGC 6207 is starting to show in the upper left, too.
You look to be well focused, Joe.

dan kowall

June 23, 2007 01:45 PM Forum: CCD Imaging and Processing/Deep Sky

Coma Cluster

Posted By dan kowall
One of my favorite areas--it's like a Hubble Deep Field for us amateurs.
Artfully done, Jim.

dan

June 23, 2007 02:14 PM Forum: CCD Imaging and Processing/Deep Sky

Crescent Nebula Test

Posted By dan kowall
I don't know how that got there, John, but, rather than being a 'green' thing, I think it might be related to the red and blue channels. Your green channel looks okay, but the red and blue channels show anomalous dark areas there. When that's happened to me, it was usually something I messed up in the calibration sequence.
An examination of your raw subs will show if the dark areas are real or not. Looking at your exposures after each processing step will show an obvious misstep.
You might want to reset your black points, too, they're a little off.
Hope this helps,

dan


June 29, 2007 11:52 PM Forum: CCD Imaging and Processing/Deep Sky

target temperature

Posted By dan kowall
Hi Charles,
Don't concern yourself with target temperatures, but with the % of cooler usage. Start with a cooler temperature about 15 degrees below ambient and work your way down until the cooler is working at about 75%. As a general rule, you don't want to go over ~80%. If you're going to experience a large ambient temperature drop during the course of the night, you can start at something higher, say 90%, and can then be reassured that you won't experience problems.
Don't bother with water cooling until you're familiar with your camera. The vast majority of users never use it anyway.
You certainly don't want to be taking flats while the camera is cooling. Wait until it's stabilized. I take flats and especially darks at the end of a session.
Do you know what frost on the cover slip looks like? It certainly sounds like that is what you're experiencing. Post a jpeg of what you're seeing if you're unsure. It's an easy fix-just bake your dessicant. Follow the directions and don't forget to take the O-ring off.

dan

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