Quote:
Originally Posted by PRejto
Hi Ray,
Thanks so much for this work. I think it will really benefit my images if I follow this rule of 10X!!
Question. Some time ago someone on this forum suggested that I take flats at higher adu than the typical 20-30k adu. The claim was that fainter stuff would be visible. So, say if I aimed for 40,000 adu flats what does this do? And, in your opinion is there an advantage or disadvantage to such an approach?
Thanks!
Peter
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Thanks Peter - yes, I am going to have to go back over some past data where I mucked up the flat calibration
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As far as I can tell, the only two conditions for flats is that they have to be taken in the linear region of the CCD and it makes sense to get well above the read noise. Depends on the CCD, but those conditions should pretty much always be met if the ADU is between 10,000 and 40,000. In terms of the final result, 40 flats of 10,000 ADU should be identical to 10 flats of 40,000 ADU. The only ways I can think of that this could break down is if you use stacking software that only has 16 bit fixed point internal data representation (I don't think anything modern is in that category), or you use median stacking for the flats (but why would you?). regards ray