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Old 24-08-2016, 11:18 AM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
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Yes you do. There is no gain or offset on the SBIG STF8300.

Chose a temperature you should be able to achieve on a regular basis. I chose -20C for my ST8300.

Cool the camera to -20. Then set the software to bias ( I use CCDsoft and sometimes SkyX and you set what type of image you want it to take).

I take about 18 for a bias. Some take more but I am not sure it really makes any difference to do more. I used to use 6.

Take say 16 at 1x1 binning and 16 at 2x2 binning.

Settle on a likely exposure time you will be taking. That would depend on how good your tracking mount is (worse mounts need shorter exposures) and if you plan to do narrowband or LRGB only. Narrowband generally need longer exposures to reduce the noise.

I use 10 minutes for both but my scope is large and fast. I also use 5 minutes.

So take say at least 6 darks 1x1 at both 5 and 10 minutes -20C.

Now you need to make these into a master bias 1x1 -20C, bias 2x2 -20C, dark 10mins 1x1 and 2x2 -20C and 5 minutes 1x1 and 2x2 -20C.

Save the masters with the file names as above for easy finding later when you need them.

I label mine Bias or Darks and then what type for example
Bias 1x1 -20C
Dark 10mins 1x1 -20C.

So later when you are processing all your darks will be together and biases together so they are easy to find.

You will also need to take flats. That's another discussion.

Having done the above when you now image you use either 5 or 10minute subexposures and set at -20C so everything matches up.

Darks need to be redone every now and then, say 6 months or when they start to not work as well. CCDs deteriorate over time. The 8300 may develop new vertical lines you want to see removed when processing, new hot pixels show up.

Greg.
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