SCOPE: Celestron 9.25 CGEM GUIDESCOPE: Orion Awesome Autoguider CAMERA: Unmodded Canon T3i BANK ACCOUNT: Empty
Chris TS 65mm EDQ Orion 80ST NEQ6 GoTo Mount ASI120MC Orion StarShoot Autoguider Atik 428EX Canon 550Da (modded)
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Starlight Xpress Lodestar Autoguider
Canon EF 200mm f/2.8L II USM
Olympus Zuiko 50mm f/1.8
SV115 APO/CGEM Mount/SXV-H18 CCD/Orion SSAG & ST80 Autoguider System
AT8RC with Moonlite & Stepper Motor
Skywatcher 120mm ED PRO
Skywatcher HEQ5 with EQMOD, KWIQ Guider
Nikon D5100 Baader mod by Brent Oliver
12" GSO Dob with Argo-Navis, 102mm Skywatcher Short Tube
Quote:It looks like both your stacked image and your raw sub have had a stretch applied to them.
Quote:If your sky allows, do 5 or 10min subs; raise the ISO to 800 or 1600.
Quote:I think you are expecting too much at this focal length.
1987 Meade LX3 2120 10" SCT on hypertuned EQ6 Pro Baader Self-Mod Canon XS_CLS Clip Filter DSI color_Orion ST80 Coulter 10" Compact Odessey Dob http://www.astrobin.com/users/shawnhar
Quote:Quote:It looks like both your stacked image and your raw sub have had a stretch applied to them.
I have not stretched anything... those are the pics directly from the camera and DSS converted to JPG.
I am not sure what that tell you.
Quote:Wow! I had now idea about this dss auto stretch. Thanks Scott. Also, looking at your Quintet image, I see that 3 minutes is plenty of exposure! Great image!
Quote:I am learning from this thread, too.What are calibration frames? Is that a generic term for the groups of flats, bias, and darks?Thanks!
PeteGallery: http://www.astrobin.com/users/pmumbower/CGE Pro | modded C9.25 | 8" f/4 newtSBIG ST-2000XM, CFW-9 Astronomik type2c LRGB, Baader 7nm HaQHY5L-II mono, PEMPro2, Sequence Generator Pro, PixInsight, RegiStar
Quote:I'm gonna guess one of 2 things....
1st, this image was taken through clouds, maybe high thin clouds you couldn't see, but that is the most likely case. I have had the same thing happen, flat's can't fix it because the gradients are changing frame to frame.
2nd and hopefully less likely, you have crazy multiple light sources around like neighbor lights or you are shooting through/close to light sources. Flats can't fix that either because the target is moving, therefore the gradients are moving frame to frame.
I gave a go in Star Tools but like Ivo said, very difficult to doa anything with it in post processing, those gradients are pretty rough. I tried using masks for the galaxies and "isolate" in the Life function.
Quote:A few questions - 1) With your flats - is the orientation of the camera unchanged from the time you take your flats until the time you start capturing?2) When you captured your flats, did you have the CLS filter in place (and left it the same until you were capturing data)?3) When applying your calibration frames in DSS - are you sure you have all of the correct frames in the right place (i.e., you didn't swap dark frames for flats, or some other type of mistake)?4) Would you mind posting one raw .CR2, your Master Bias, Master Flat, and Master Dark frames?
Quote:As a control test, have an ICNR session to rule everything else out, other than calibration. Thx
Quote:First don't save your file from DSS instead make a copy of the autosave.tif and then use imagemagick to convert it to 16 bit. My understanding is that DSS has a bug in the 16bit save routine.
Quote:I think I see the problem. Your "Master Offset" file doesn't look like its taken correctly. A Bias frame (or offset) is a frame that it taken for the least possible time with the camera covered (usually around 1/4000th second). It should be VERY dark - it only contains read noise. Your master offset looks like its a properly exposed image.
Quote:I am not sure if somehow somewhere they got mixed up,