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Joselo
super member
Reged: 02/26/08
Posts: 146
Loc: Texas
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Hi all,
Last night, we finally had nice clear skies here in Houston TX. I took my Canon Rebel XTi 400, and decided to shoot M13. After processing in Nebulosity, my final stack, the core of M13 is a greenish color. How can I fix this? What am I doing wrong.... I am still learning how to process my images, all your input will be highly appreciated 
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APM 115 design by TMB
SV80S, and bunch of accessories
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Gus_Smedstad
professor emeritus
Reged: 07/02/06
Posts: 502
Loc: Boston 42° 16' N 71° 08' W
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I know diddly about Nebulosity, but in IRIS, you have to do a white balance step. The camera's sensor has 2 green masks for every red and blue lens, so anything that processes RAW files will come out green unless you adjust this. Jim Solomon's cookbook recommends 1.96x red and 1.23x blue multipliers for an unmodified Canon SLRs.
Photoshop also has tools for removing color casts which do the same thing. You click an eyedropper on something that's supposed to be gray or white, and it multiplies the color values accordingly. This can be kind of rough to find with an astro image if it isn't of something color neutral like a galaxy core.
- Gus
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Gus Smedstad
Orion Atlas 8 EQ-G
Orion 80mm f/11.4 guidescope
Orion Starshoot Autoguider
Canon 40D
Philips SPC900NC
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ChazK
Pooh-Bah
Reged: 11/23/05
Posts: 1389
Loc: Melbourne, Florida
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Gus!
You did not sell your eq! That's fantastic!
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Tak TOA 130mm/NJP Temma2
Tak FS 60CB
Canon 40D (unmodded)
Astronomik CLS
Canon EF 28-135mm f/3.5-5.6
www.digitalunatic.com
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Gus_Smedstad
professor emeritus
Reged: 07/02/06
Posts: 502
Loc: Boston 42° 16' N 71° 08' W
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I haven't used it, either. Though I did get as far as setting it up a couple of nights ago when CSC said it'd be good but in fact it ended up badly overcast.
I bought a Stiletto and set up EQMOD to help with the pointing issues. Hopefully I'll find it less frustrating this time around.
- Gus
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Gus Smedstad
Orion Atlas 8 EQ-G
Orion 80mm f/11.4 guidescope
Orion Starshoot Autoguider
Canon 40D
Philips SPC900NC
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ChazK
Pooh-Bah
Reged: 11/23/05
Posts: 1389
Loc: Melbourne, Florida
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Doubtful my friend but keep the faith. It only takes one nice image to turn it all around (I'm still waiting of course) but it's out there!
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Tak TOA 130mm/NJP Temma2
Tak FS 60CB
Canon 40D (unmodded)
Astronomik CLS
Canon EF 28-135mm f/3.5-5.6
www.digitalunatic.com
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Joselo
super member
Reged: 02/26/08
Posts: 146
Loc: Texas
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Thank you Gus...
Jose
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APM 115 design by TMB
SV80S, and bunch of accessories
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ericjacob613
Photon Hog
Reged: 05/25/07
Posts: 2870
Loc: Santa Barbara CA
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Jose, can you post an image for us to see?
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Joselo
super member
Reged: 02/26/08
Posts: 146
Loc: Texas
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I created a new post, but lets continue this thread... I played a little with Nebulosity and I finally came up with this image
From my other thread
QUOTE
This is my first attempt at M13, I have been waiting for clear skies here in Houston, and I am very pleased with the results.
Please feel free to criticize. Also, What can be done to avoid oval shaped stars on the edges of the image. This is a cropped version of the original image, so you cannot see too much of it.
Equipment used:
StellarVue SV80S
Atlas EQ-G Mount
Canon Rebel Xti 400 Unmodded, 10 Darks, No Flats, No Bias
28 RAW subs, iso800, color, 30sec each, captured, preprocesed and stacked in Nebulosity, Postprocessing in Photoshop CS2
UNQUOTE
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ericjacob613
Photon Hog
Reged: 05/25/07
Posts: 2870
Loc: Santa Barbara CA
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That image looks just fine. Here's a quick adjustment done in Photoshop. I Curved the red channel up a bit. It's still not perfect, but it has a lot of potential.
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Joselo
super member
Reged: 02/26/08
Posts: 146
Loc: Texas
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Thank you Eric,
that looks more natural....
jose
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APM 115 design by TMB
SV80S, and bunch of accessories
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|
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