Thread: Photometry
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Old 26-03-2010, 10:16 PM
Karls48 (Karl)
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Karls48 is offline
 
Join Date: Jan 2006
Location: Sydney
Posts: 753
Thanks Ivan and Terry. You have been very helpful.
Yes, my camera’s maximum exposure time is 2.56 seconds. Frame integration = 1/25fps = 0.04 * 128 (maximum frame integration) = 5.12/ 2 (interlaced camera) = 2.56 seconds. The shutter can be set from 1/12000 to open (but for 2.56 sec only) and its CCD chip got anti blooming feature. The Maxim Dl got variable anulus.
I have been stacking subs with median feature – that may be part of the problem. But I can select sum or average or sigma. Next imagining session I will find the linearity of my camera.
Software I’m using displays a lot of information about the star in the anulus. ADU (analogue to digital conversion – multiplying this number by gain gives number of photons per pixel), SNR, flatness, star magnitude, catalogue magnitude, catalogue identifying number and few more parameters that I don’t understand.
And I will revisit Flat frame acquisition. It may work this time.
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