Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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I've been using a Hap Modded Canon 30D with Baader UV/IR filter for a little while now and I'm not happy with these strange bands across my images! I've shot before with a Canon 5D at up to 25 minutes without anything similar. It seems I get these bands regardless of exposure time, ISO, filter, telescope, etc.
I've shot H-alpha and RGB with 2 different scopes and I have these bands with both. My typical exposures are ~4-5 minutes @ ISO 800. These bands appear differently in my R,G, and B channels which leads to off bands of color in my RGB images. It only becomes noticeable when the images are stretched significantly but that's what happens 98% of the time.
So is this the camera? Does everyone else put up with this but not talk about it? Is it a Baader filter defect?
Here's a H-alpha shot, which shows the defect clearly. I don't have a common workflow to get rid of it; darks, flats, etc. don't do anything. Flats are all converted to grayscale so the different color intensities of the bands are not addressed.
So, what do I do? It's a new camera with a new Baader mod that isn't working right and it's getting me all worked up because summer is right around the bend and I don't have the money to try another modded camera. Help!
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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Can this be interference?
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
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It could be a camera problem, but there are workarounds that you can try. For one thing, splitting out the R,G,and B channels of your flats and applying them to the R,G, and B channels of your lights should hide it.
Does this show up in darks or bias frames if you stretch them?
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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I've stretched darks and flats and can't find this. It appears that there MAY be fewer hot pixels in the areas of the bands but hard to tell if I'm just seeing things. I haven't been able to see them in my flats when stretched and therefore haven't been able to correct it that way.
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
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Quote:
Can this be interference?
If it's always in the same place it's within the camera. If they move up and down from frame to frame it could be a power supply problem.
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
|
Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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It seems to be in the same place. Here's another example of an RGB image broken down into RGB channels:
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
|
Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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Red Channel:
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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Blue Channel:
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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Green Channel:
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
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That'd be irritating, all right. Can you post a stretched dark frame of similar duration?
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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Yes: Here's a single dark stretched in ACR.
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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So obviously it's the camera from this but why aren't my darks compensating for it then?
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
|
jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
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Quote:
So obviously it's the camera from this but why aren't my darks compensating for it then?
Yup, it's there!
That's good news; means it can be corrected. Your question, of course, is the right one. It should be possible to make the darks do the job. How do you apply your darks now?
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
|
Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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I just noticed that my darks are all grayscale in DSS so that might explain that. Can DSS do darks and flats for each color channel?
--------------------
Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
|
jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
|
|
Quote:
I just noticed that my darks are all grayscale in DSS so that might explain that. Can DSS do darks and flats for each color channel?
Now we're gonna have to bring in an expert; I don't use DSS. 
You are very close to the solution, though.
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
|
Bert
sage
Reged: 02/17/06
Posts: 430
Loc: Australia
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Try using in camera noise reduction (ICNR) and then stretch and see if the effect has disappeared. You can just do a long exposure with the lens cap on with and without ICNR on and then see what the difference is.
If in a lit room cover the viewfinder to stop stray light getting in to the camera.
I always use ICNR as I have tried everything and NOTHING comes close!
Bert
Edited by Bert (04/13/08 08:05 PM)
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Strgazr27
Vendor - Deep Space Mods and Composites
Reged: 10/04/04
Posts: 6984
Loc: StonyHill Observatory
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I can tell you that I have never seen that banding in the 2 30D's I modded nor in any of the other cameras I have done. Are you using the AC adapter from Canon or a grey market piece?
CS's
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Bobby
StonyHill Observatory
Skywatcher EQ6 Pro (On it's way)
AT 130 F/6 Prototype
Royce 10" f/4 Astrograph (Under Construction)
Self Modded 40D
70-200 F2.8 L IS
SSAG
YAHOO TMB 130SS Group
Astronomy Technologies Yahoo Group
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Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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I'll try the ICNR and see. That sounds like an interesting test.
I use the Canon AC adapter with batter --> AC, generator, or household AC with the same bands.
Thanks for all the help so far guys!
--------------------
Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
|
jrcrilly
Refractor wienie no more
Reged: 04/30/03
Posts: 25196
Loc: NE Ohio
|
|
Quote:
I'll try the ICNR and see. That sounds like an interesting test.
That'll definitely tell us something!
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John C
Urban Observatory
A&M/Astreya 76mm F/6 APO
TMB/LOMO 80mm F/7.5 APO
Tak FSQ-106N F/5 APO
Meade 178ED F/9 "APO"
Meade ETX-125AT
C14
Teeter 20" F/3.8 truss Newt w/ServoCat
CI-700, NJP, GPDX/SS2KPC, CG5-GT
ST-10XME, DSI Pro
|
Nate B.
sage
Reged: 03/08/07
Posts: 282
Loc: Pittsburgh, Pennsylvania
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|
Here's 5 minutes @ ISO 1600:
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Tak FSQ-106EDX
Pentax 75 EDHF 75mm f/6.7 APO
Apogee Alta U8300 CCD
Orion Atlas EQ-G Mount with EQMOD
|
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