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Old 27-08-2019, 06:30 PM
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gregbradley
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Join Date: Feb 2006
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Quote:
Originally Posted by Manav View Post
Hi Greg - First of all thanks for your prompt response. I'm new to CCD imaging so I apologise in advance.

I've linked the FITS file for Dark frame which is a 300sec exposure at -20 taken using SIPS software as well as a 0.2sec bias frame taken at -20 in the below link.

https://drive.google.com/drive/folde...hJ?usp=sharing

Unfortunately, I do not yet have a flat field generator so I did not have any flat field shots. I also do not have another scope to test on :/

I didnt even consider light pollution; I have been shooting all images at South - South West at 40deg above horizon from the backyard so that could be a possibility.

I'm using a SVQ100 so the image is inverted which could explain why the light gradient is on top of the image.

Just to confirm if this was a CCD issue we should see the same glow in the darks and bias am I right?
Yes I would expect to see something in the darks, bias and the flats. Some scopes have a centre hot spot which is more common now that many have corrector lenses which can cause that effect. This is not what you have though.

It looks mostly like light pollution if the image is inverted. I discounted that at first because light pollution would be at the bottom of the image not the top.

But yes most images are reversed top/bottom and left to right.

Greg.
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