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A few comments on setting camera data
I am currently using a ZWO ASI1600MM-cool camera.

In the "Edit Camera Data" dialog, there are boxes for Read Noise, Dark Signal and Bit Depth.  The read noise and dark signal are labeled in units of electrons and electrons per second.  Presumably, this data will be used for exposure length calculations.

My comment is that all the imaging software that I use (either SGP or MaxIm/DL) will scale the image to 16 bits by shifting each pixel's ADU left by 4 bits, effectively multiplying each pixel by 16.  So I assume that I need to tell ST4 that this is a 16 bit camera so that any math based on ADU levels will work out. If so, this is a bit confusing.

Another comment that I have is that I use a few specific gain/offset combinations with this camera.  For each of them, I have computed the actual read noise (and have the data available in both electrons and ADU @ 16 bits).  I've also computed the actual gain in electrons per ADU.  I notice that ST4 has just a single option to set the read noise, even though it varies significantly between the different gain/offset settings.  It would be nice to be able to associate read noise with each gain/offset that I use.  Also, getting back to units, it's unclear what to do for the offsets.  I assume that if I've characterized the camera as 16 bits, that it will work out.

Hi Wade,

The reason we want to know the ADU values is to ensure that we don't clip the signal, and this all happens in the camera long before post processing. What happens in post processing is not important to what SkyTools does.

The true read noise does not depend on the Gain setting of the camera. It only appears to depend on it because the gain setting alters what you measure after the gain is applied. This is naturally taken into account when SkyTools does ts calculations, all of which are independent of the gain setting.
Clear skies,

SkyTools Developer

There are sometimes misconceptions surrounding gain, especially for the ZWO cameras. Because SkyTools consideres gain directly, there isn't much one has to do in the way of calculations. There is a section in the SkyTools help that discusses how the gain should be used. See the Topic "Setting the Camera Gain (Including ZWO Cameras and DSLRs)."
Clear skies,

SkyTools Developer
Thanks. I'll read that.

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