Old 28-05-2009, 01:31 AM
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MelD (Melvyn)
Mel Davis

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Location: Sydney Australia
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Orion Starshoot DSCI-II

Hi there.
I've recently purchased an Orion DSCI-II CCD camera and the initial images I get (lunar shoots for a start) are heavily overlaid with a matrix that looks like the pixel array of the chip. The folks at Bintel suggest that this is because of the short exposures required for such a bright object, and what I an capturing is the interlacing. However having tried an ND filter, and more recently a hydrogen alpha filter, to cut down the light and increase the exposure, I still have the same problem. It is particularly pronounced when shooting RAW images.
Can anyone please advise me?
Skywatcher ED80/EQ-5 Pro mount
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Old 28-05-2009, 03:56 AM
Dazzled by the Cosmos.

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Join Date: May 2005
Location: Brisbane
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Hi Mel

At face value, this sounds like you are seeing the “Bayer Matrix”?

Most one shot colour ccds have an arrangement of a repeating array of RGBG micro filters over the chip, so that Pixel 1 records the Red data, Pixel 2 records the Green data, Pixel 3 records the Blue data and Pixel 4 records the Green data (again).

Processing software “should” be able to de-bayer the image so that this grid disappears and you are left with a “clean” image.


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Old 28-05-2009, 10:32 AM
Bolts_Tweed (Mark)
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gday Mel - I have had one a few months now and I have to admit I have never seen what you are describing. I have attached a unprocessed lunar image taken one weekend at the observatory when I couldnt stand sitting watching TV with the boss and decided to go play in the obs. It is a raw light straight out of the camera just stretched to 8 bit for jpg conversion - no other processing (obviously - its not real good ).

It was a.005 sec image taken through a ED120. So in short I dont have an answer for you but if you want me to reproduce your exposure, scope etc I will have a go this weekend (We have a couple of hours to moonset)

Do you have an image of of the anomally - hopefully by reproducing the whole set up (A mate has a Skywatcher ED80) it will show if it is just your camera or is general thing of the camera and exposure time etc.

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Old 28-05-2009, 11:14 AM
Bolts_Tweed (Mark)
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Mel - just had another thught - sorry if it is a dumb question - I dont know everyones level of experience yet - but is the grid square to the frame of the Chip (ie vertical and horizontal lines) - I assume it is but I thought I would check. Or is it offset to the horizontal at an angle. If it is a series of lines offset at an angle it could be an easy fix.

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