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M2 Globular Star Cluster in Aquarius

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Old 12-21-2006, 11:12 AM
CharlesBell's Avatar
CharlesBell CharlesBell is offline
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M2 Globular Star Cluster in Aquarius

M2 Globular Cluster
Alias: NGC 7089
Constellation: Aquarius
Located West of Sadalmelik and North of Sadalsuudof
RA: 21h 33m 27s Dec: -00°49'22"
Size: 16.0 x 16.0 Magnitude: 6.6

Image Link:

Imaged: September 14, 2006 with good seeing
Image Aquisition: 10 x 120 seconds with CCDOPS
Telescope: 12 inch Meade 200LX-GPS at f/6.3
CCD: SBIG ST-2000XCM Single Shot color (1600 x 1200 7.4 micron pixels)
AO-7 adapative optics guide unit
Image calibration with dark and flat frames.
R,G,B channels extracted with CCDOPS
Alligned with CCDSoft
Median combined by color into Fits images for R, G, and B.
Imported into PhotoshopCS2 R, G, B color channels after log stretch
with NASA/ESA FITS Liberator
Cropped and centered on cluster midpoint and restored to 1600 x 1200
Sucessive Levels/Curves/Colors layer adjustments
Noise Reduction tool in PhotoshopCS2 applied with slight sharpening.
Gaussian blur applied to Dim zone
Smart Sharpenng filter applied to Bright Zone
Color Bias adjusted with Levels
Attached Images
File Type: jpg M2-09142006.jpg (83.7 KB, 41 views)

Last edited by CharlesBell; 10-15-2010 at 05:23 AM.
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Old 12-26-2006, 09:49 AM
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CharlesBell CharlesBell is offline
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Re: M2 Globular Star Cluster in Aquarius

Comparison images can be viewed at the following link which is a search result from Google images

I would appreciate any critique comments or just a note to say hello.

I realize that this image is very different from most of the images on this site.
If you look at other images from the above link, you will see that this object is extremely bright at its core. This makes processing to bring out the core stars very difficult. And to give color to the core is even more difficult.

It was the very careful application of levels and curves in sucessive adjustment layers in PhotoshopCS2 that made this possible.
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Old 12-26-2006, 07:32 PM
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cardmnal cardmnal is offline
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Re: M2 Globular Star Cluster in Aquarius


Very cool indeed . I just bought the family a telescope (probably not a very good one) for Christmas and would love to find a star cluster like that. Unfortunately it has been cloudy ever since we opened it.

Even if I find something cool like that I am not sure how to go about getting a photograph of it. Is there some kind of adapter or something for a camera I should get?

Thanks, Alan
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Old 12-26-2006, 11:12 PM
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Craig Walters Craig Walters is offline
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Re: M2 Globular Star Cluster in Aquarius


i'm not going to pretend to know as much as charles here, but look at the specs he posted. astral photography is quite a bit different than almost every other type of photography. it's quite specialized and takes specialized equipment. notice his exposures... 10 at 120 seconds each. and notice the tracking motor on his unit. you pretty much HAVE to have a tracking motor on the telescope to keep the body you're shooting in a relatively stable position, body to telescope, or you simply lose the image.

the earth's rotation is quite fast and this moves you around, along with your telescope, relative to what you're shooting. i had a scope as a kid and i'd no more get something like the moon in the viewfinder and by the time i'd look into the normal eyepiece, the moon would already be part way out of the view.

you also need a VERY steady base for the scope. any motion on the scope itself, any slight jiggle and the shot is ruined. my one as a kid had a very flimsy tripod and even the slightest wind would jiggle the thing. not a good thing for long exposure times.

you'll also need a camera mount if the scope didnt come with one, and a camera with either either a manual remote clicker or a timer with a decently long time to keep the shutter open and still.

back when i had the scope, i didnt have a decent camera. but it was always fun looking at different things in the sky.

night exposures are always difficult, but add in motion and you've got some very tricky things to deal with.
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Old 12-27-2006, 07:37 AM
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LQQKER LQQKER is offline
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Re: M2 Globular Star Cluster in Aquarius

Looking at the thumbnail I thought this was a photograph of M-13 (Globular cluster in Hercules). That said, you did a fine job on the image, especially resolving the stars on the bright center.

You may already be aware of this, but one of the tools I use to help resolve images is a "free" plug-in from reindeer graphics called "adaptive equalization". If used sparingly on the original photo it can help to bring out additional details as well.

Astronomy is one of my hobbies, I have a 10" light bucket and a 4.5" refractor. During the last year it seems I have difficulty finding clear skies when I have the time to view, but you know how that goes.
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Old 12-27-2006, 09:23 AM
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patriciakay patriciakay is offline
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Re: M2 Globular Star Cluster in Aquarius

Hello Charles...

I love this photo and your description of it...
Photography is one of my many hobbies...We also have a telescope, quite a powerful one and have looked at many moon shots over the years...I find it really interesting...

Thanks for sharing your photo and i look forward to more!!!

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Old 12-27-2006, 02:52 PM
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CharlesBell CharlesBell is offline
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Re: M2 Globular Star Cluster in Aquarius

Wow, thanks for all the comments and the suggestion on the plugin.
I was up late last evening with three faint comets I have been observing over recent months.

I really appreciate Kraellin's explanations as his may be better than mine.

The first thing one will learn about astrophotography is that there is nothing easy about it. It takes time to learn how to bring it all together to make things happen. Its a continuous uphill struggle.

The telescope I use is equitorially mounted. That means it will rotate with the earth. It has to be precisely aligned with celestial north. My scope weighs about 125 pounds. It has to be balanced with the camera attached so as not to wear out the synchro motors. Its a "go to" type, which means it has its own computer processor and a hand controller and can be slewed automatically to any target after synchronizing with a few bright stars. That makes finding faint objects much easier.

Once I get the object I want to image in the field of view with the camera you have to focus precisely. This scope has a micro focuser which I can precisely focus on small faint stars with the aid of the camera.

Tracking is the most difficult aspect of astrophotography. My typical field of view is about 20 x 15 arc mnutes which is wide enough to take in most globular clusters. The tracking must be down to the arc second to get round stars. The telescope mount makes all the differnence here. To correct for the tiny variations in the gears and motor movement, I use an Adaptive Optics unit which tilts a mirror in the optical path to keep a guide star centered on a separate guiding chip several times a second.

Whatever camera or scope you have, start by imaging the moon. Then perhaps move to either wide field camera shots with deeper and deeper exposures. Or try imaging Saturn or Jupiter.

I have imaged all nine planets including Pluto many many times. There are different challenges with each one. I love to image Uranus and its primary moons as well as Neptune and its moon Triton, and Pluto. One of my Neptune/Triton images was published by Sky and Telescope in the October 2006 issue on page 59. My primary study is on comets. The Minor Planet Center calls me C. Bell H47 Vicksburg.

Best wishes!
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