Applying a flat frame manually

[umadog]

Hi,

I want to "manually" apply a flat frame (not through specialised astro processing software but in Octave). Obviously if I divide my image by a non-normalised flat then the scale of the resulting corrected image will change. My corrected image is floating point, so I'm currently thinking of just re-scaling it and converting it to 16 bit integers so that it uses up the whole dynamic range and takes up not too much space on my HDD. Is there a better way, such as normalising the flat somehow and doing everything with integers and not floating point, that I'm overlooking?

Thanks!

[carastro]

You've lost me.  I am sure there is a way to do it in photoshop though.

Look at the end of this tutorial on how to create an artificial flat.  Ignore the first bit, just go to how to combine.

http://ccdastro.pwp.blueyonder.co.uk/gradient_removal.htm

Carole

[umadog]

I'm doing this programmatically (Python, Octave, C++, haven't decided). An image processing program is a no-go because I need a very high level of automation. 

[umadog]

One suggestion is here: http://www.twilightlandscapes.com/IRAFtutorial/IRAFintro_05.html (part E)