Phrozin R/T TT
sage
Reged: 02/22/05
Posts: 288
Loc: USA-Florida-Bay Area
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OK so I got my "first light" with my DSI 2 nights ago, and tried my hand at post processing last night for the first time. After many failed attempts I finally got a clean image, but there is a lot of green "motled" color in the center region of M42. I saw in this thread that some others had the same green color. Is this color due to lack of experience of post- processing, or is it due to the DSI itself?
Maybe even in IR filter in the DSI?
here is the image I came up with (it's no where near the quality you normally see in this forum so don't expect much lol)
Thanks for any information you can give,
Phrozin
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jgraham
Postmaster
Reged: 12/02/04
Posts: 11575
Loc: Dayton, Ohio
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A couple of quick thoughts...
What were the exposure conditions? Telescope, exposure time, how many, combined? etc.
The fact you have the Trapezium resolved suggests the exposure was relatively short so there may not have been a lot of signal for the software to work with in the nebula. Also, I've had better results using the soft color balance rather than the sharp color balance, though I wouldn't mind reading other's experience with soft versus sharp.
-John
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-John
The best advice on imaging I've ever been given... don't forget to look! 
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Phrozin R/T TT
sage
Reged: 02/22/05
Posts: 288
Loc: USA-Florida-Bay Area
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Quote:
What were the exposure conditions? Telescope, exposure time, how many, combined? etc.
Opps,
I forgot to give that info. 
the image above is made up of:
Image: 10x1sec, 10x2sec, 10x4sec, 10x8sec, 10x15sec, 10x30sec
Scope: LX200 GPS SMT 10"
Focal reducer: SAC f3/f5 Focal reducer
Camera: DSI without wedge
Location: inner city (heavy light pollution I live 1/4 mile from an airport  )
Time: 10:20 PM to 1:20 AM
Seeing: Partly cloud
Transp: was ok, but have seen better.
Temp: started at 77 Degrees to 59 degrees
I think thats all the info needed, but not sure.
as reference, this is a single 30 sec shot.
Phrozin
Edited by Phrozin R/T TT (03/22/05 05:13 PM)
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jgraham
Postmaster
Reged: 12/02/04
Posts: 11575
Loc: Dayton, Ohio
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Ahah! You're on the right track. I love the beautiful detail around the Trapezium. I'd like to revisit this area to concentrate on the inner nebula.
For starters I'd suggest using 15sec exposures and leave the camera in live mode without dark subtracting. Set the Save Procc to BMP, Normal, and combine with the acceptance level set to 0% so it uses every frame. With the camera idling in live mode turn the auto contrast off and adjust the black/white point of the histogram until the image suites your taste. This mode is similar to using film; you'll have the choice of recording the beautiful detail in the inner nebula or washing out the inner nebula to record the fainter outer nebula. Leave the Gain and Offset at their default values. Once the histogram is set to about where you want it do a soft color balance, you may have to tweak the histogram again. Once this is all set you're ready to go. Select a star near the center of the field for tracking and go for something like 20x15sec. That should be short enough that field rotation should be a problem.
This combination should be a good place to start from. Once you have the basic operation of the camera under control you can start changing things. Be sure the read Suk's review of the DSI in the Cloudy Nights Reports section, he's got some very good tips for beginners and specifically uses M42 as an example.
Have fun!
-John
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-John
The best advice on imaging I've ever been given... don't forget to look!
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