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M4

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#1 Jim Thommes

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Posted 17 July 2013 - 10:34 PM

Here is a wide field image of M4. M4 is in a pretty interesting region of the sky in Scorpius so it's not often singled out in an image in which it is the sole object. Image and details are here:

........ Posted Image

http://www.jthommes.com/Astro/M4.htm

Scope - FSQ-106N refractor at f/5
Camera - Artemis285 (Astronomik LRGB filters)

#2 DavidC

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Posted 17 July 2013 - 11:54 PM

Wow Jim what a great image of M4, the details and star fields look excellent! How in the world did you get clear skies in San Diego enough to image? Maybe the monsoons don't hit you like they do out here, or there must have been a break in the clouds. Thanks for sharing.
David

#3 Dan Crowson

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Posted 18 July 2013 - 02:19 PM

Nice image Jim.

I'm a little curious. I think most people shoot 'stars' just using RGB. Do you find that the luminance adds to it?

Dan

#4 dsnope

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Posted 18 July 2013 - 03:32 PM

That's a great M4, Jim. With it's great resolution I expected to see the name EdgeHD below it but to my surprise you did it with the Tak. Nice.

#5 David Pavlich

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Posted 18 July 2013 - 04:19 PM

That's good stuff, Jim!!

David

#6 Jim Thommes

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Posted 20 July 2013 - 12:00 AM

Thanks for the comments folks.

#7 Jim Thommes

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Posted 20 July 2013 - 12:06 AM

Wow Jim what a great image of M4, the details and star fields look excellent! How in the world did you get clear skies in San Diego enough to image? Maybe the monsoons don't hit you like they do out here, or there must have been a break in the clouds. Thanks for sharing.
David

David,
It's kind of like between fire and ice here - only its the marine layer and the monsoon. Interestingly enough, about 40 miles inland, we can frequently be between the two. But truly, monsoon doesn't come with a vengeance until August.

#8 Jim Thommes

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Posted 20 July 2013 - 12:15 AM

Nice image Jim.

I'm a little curious. I think most people shoot 'stars' just using RGB. Do you find that the luminance adds to it?

Dan


Dan,
Thanks.Yes most imagers probably just shoot RGB's I do LRGB's mostly out of habit and consistency of work flow. I have actually never done an RGB only so I can't really say which is better. I think some would argue that with RGB's only of the appropriate binning for full desired image resolution that you will spend less time collecting the data. Or put another way, a better S/N for the same amount of exposure time.

#9 Rick J

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Posted 20 July 2013 - 01:58 AM

Another nice one to make me envious of your latitude. I won't be catching this one unless those tall tales about Planet X tilting the earth's axis were true.

I've never found RGB to be faster than LRGB. I sometimes do it for clusters since it doesn't go as deep allowing me to punch cluster stars out of the background more easily.

At one time I could get better star color with RGB but as my skills improved that's no longer true for me. As I've gotten better at suppressing background stars I haven't done RGB in some time. Might save time in image processing but takes up far more imaging time to reach the same S/N, at least for me. Others seem to prefer RGB color. Do what works for you is my philosophy and not worry about how others do it.

Rick






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