OSC bias and darks

[RobH]

Hi all.

I recently acquired a 'One Shot Colour (OSC)' CCD and was wondering about calibration frames.

I need to subtract bias from my flats before applying them.

Do I apply a boxcar filter to the bias subs to remove the bayer matrix before combining them into my master bias?

Do I do the same with my darks?

Thanks in anticipation.

Rob

[harry page]

Hi

I presume you are using maxim ( boxcar filter )

Any way no , just apply the filter to the flats only

Harry

[RobH]

Thanks Harry.

Does that mean that I debayer the bias and dark subs before stacking them?

Do I apply the boxcar filter to the individual flat subs, or to the stacked master flat?

Rob

[steppenwolf]

I agree with Harry, apply the boxcar to the flats only and use a Median stack for the FLATS and an average for the BIAS. You won't need DARKS for the M25C IMHO.

Does that mean that I debayer the bias and dark subs before stacking them?

Do I apply the boxcar filter to the individual flat subs, or to the stacked master flat?

Maxim will do all this for you automatically when it produces the Master BIAS and Master FLAT frames in the 'Set Calibration' routine.

[harry page]

All calibration is carried out prior to debayering , and you do not debayer the darks or bias but debayer the flats , the boxcar filter destroys the colour data

Here how I do it in AA4

http://www.harrysastroshed.com/AA4flat.html

I prefer to make individial master frames

P.s.

Slight change of heart I can not remember if you need to debayer the flat or as in AA4/5 the filter just destroys the bayer pattern

[ollypenrice]

I followed Harry's AA method since I use AA anyway. Works a treat for me. I failed to credit him in my AN article for which I grovellingly apaolgize.

One set of flats instead of four; yesssss!!!

Olly

[steppenwolf]

Slight change of heart I can not remember if you need to debayer the flat or as in AA4/5 the filter just destroys the bayer pattern

It isn't necessary to de-Bayer the Flat separately , the boxcar filter effectively does this for you.

[harry page]

I followed Harry's AA method since I use AA anyway. Works a treat for me. I failed to credit him in my AN article for which I grovellingly apaolgize.

One set of flats instead of four; yesssss!!!

Olly

I will let you of this time

[harry page]

It isn't necessary to de-Bayer the Flat separately , the boxcar filter effectively does this for you.

Cheers will stick that in my brain for future use

Harry

[RobH]

Thanks folks

It's amazing how little information there is available on the web regarding this.

Cheers

Rob