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Saturated images

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laralds
Saturated images

Hello Community,

I have uploaded calibrated, plate solved images. When I run a time series no light curve was obtained because my images were "saturated".

 

I have a little idea of the concept when talking about regular pictures, but here I do not know what does it means nor how to fix it.

 

My student-level knowledge is kicking my behind.

 

Thank you much,

 

Pam

spp
spp's picture
saturated

When setting up your VPhot account one of the required fields is "linearity limit" expressed in ADU's.  This is the level of the signal at which the response of the camera becomes non-linear.  You can read more about this in the AAVSO CCD Photometry Guide.   You should measure this yourself.  It's quite easy to do.  The method is explained in the CCD Guide.

In Admin>Telescope Setup,  what value  is entered for "linearity limit"?  If your target or comp star contain pixels with ADU values higher than this setting, VPhot should refuse to do the photometry.  

Perhaps there is a typo there, or the value is mistakenly set too low.  If you know (by measuring it) what your linearity limit is, be sure you have entered the correct value.  If you haven't measure it, you may be able to save your data.  Measure the linearity limit, reset the value in the Telescope Setup box, and try again to measure your loaded images.  It may work.

If your linearity limit is set correctly, look at the list of comps at the upper left corner of the image display.  Saturated stars will be grayed out.  It the comp you have used is saturated, try selecting a different (unsaturated) comp.  If your target is saturated your time series is toast, but you will have learned a valuable lesson. 

Phil

 

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