[CCD-astrometry-photometry] [Aavso-photometry] SXV-H9 linearity

[Pedro Pastor]

Hello,

I find this topic very interesting. I have always wondered how binning works
with respect to the main CCD sensor parameters (linearity, gain, SNR, etc).
And I end up thinking I have no idea how binning works.

Some time ago I was told a binned CCD camera is always linear. After Gary
comment it seems to be not. How does it work? If I use 2x2 binning, what do
I get: a) The sum of the electrons on 4 different wells; b) Only 1 well
where all 4 photosites pour electrons together (up to ADC range)??

Regards,

Pedro

-----Mensaje original-----
De: aavso-photometry-bounces at mira.aavso.org
[mailto:aavso-photometry-bounces at mira.aavso.org] En nombre de
BailyHill at aol.com
Enviado el: lunes, 06 de diciembre de 2004 18:13
Para: aah at nofs.navy.mil; CCD-astrometry-photometry at yahoogroups.com
CC: aavso-photometry at aavso.org
Asunto: Re: [CCD-astrometry-photometry] [Aavso-photometry] SXV-H9 linearity

Hello

BTW, when binning, be careful!!!!   When you read out and look for a 
saturated pixel, you get the sum of the 4 or 9 pixels, depending whether you
are 
binning 2x2 or 3x3.

You can saturate several of the physical pixels without it showing up in the

summed readout.

The best way to check is to not bin, check the exposure and max values, and 
then go to the binned condition for the exposures that you keep.

My personnal experience is that this effect is quite easy to overlook, it 
occurs long before you get the classic vertical lines in the images, and it 
degraded my photometry by nearly an order of magnitude.

Gary
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