Astroart Forum

I went to try preprocessing but immediately hit two real problems. Firstly, with my main camera it is advisable to not use darks for limited exposures (eg 5 - 10 minutes). However, this means wanting to use raws+bias frames. I often don't needs flats with the smaller scope. As far as I can see from the pre-processing screen, such options to use raw+bias are not possible. Does this mean multiple arithmetic subtractions on all raws?
Second problem:I took a series of dark/bias images for the guider with comparable filenames because the info is of course in the header. When I went to load the files into the pre-proc I realised that this wasn't possible without pre-examining each one......

Have I missed some other facility?

Lawrence

I guess you are using DSLR camera.
Then if you don't use darks or flats you don't need bias.
If you use flats then you need to use bias.

I don't understand your second problem.
Are you trying to stack images from your guide camera ?
Don't you have separate light files, dark files and bias files ?
Then you need just to put the light frames in the right place and dark files in the right place - don't need bias files.

Clarification: main camera SX M25c low noise=no darks. Hence raw+bias only. Smaller scope has good field=no flats. Hence question.
Guider=Lodestar. Series of darks+bias needed because of noise. However, because fits data includes bias/dark I do not write these in filename. AAv5 requires advance knowledge of each file - hence my question (why can it not get this info from the header?)
Lawrence

Hello,
1) Just put the bias frames into the box for dark frames.
2) The SBIG fits extensions are not supported, so you will need to name the sequence with a "human-readable" name, which will help you in the future to reuse the files.
Fabio.

Thanks. BTW SBIG is not relevant here. These are Starlight Xpress cameras and FITS is the astronomical standard.....

Lawrence

In the FITS standard there are no Keys to indicate if an image is a flat, bias or a dark.

http://fits.gsfc.nasa.gov/fits_documentation.html

A program which writes them is out of the standard.

OK, I follow that. In my other program this data is set in the exposure plan and appends the info within the header (as light/flat/dar/bias).