[Shiraz (Ray)]

Hi. thought it might be worth starting a thread on practical experience with ASI1600 imaging. To start off, the following is a summary of the "amp glow" issue.

Regards Ray

the ASI1600 produces some "amp glow" that is different from the CCD experience. Although it looks a bit worrying under a heavy stretch, it is of no practical significance in almost all imaging.

First off, if you trust images rather than numbers, the attached image shows a very heavily amplified part of a 300s sub taken through a Baader O3 filter using an f4 scope (the full dynamic range of the displayed linear image corresponds to only 100 electrons). The sky that night was dark with no moon and the O3 nebulosity should have been negligible.
The measured sky noise in the region of "amp glow" (on the right hand edge) was very similar to that in other parts of the scene (you can just tell where the region is from the slight fixed pattern noise, but you have to look hard).
The sub was not calibrated in any way, but the FPN and the "amp glow" could be calibrated out if required, without leaving any significant additional noise. If you use an oversampled scope under completely dark skies and with a 3nm narrowband filter, the "amp glow" may just possibly result in slight additional noise in the edges of an image - but in all other circumstances, the "amp glow" is not an issue at all.

If you want numbers - from my camera, in the centre of a 300s dark frame taken at -15c and gain 100, the excess signal above bias is ~7-15 ADU. At gain 100, the camera produces ~10 ADU per electron (1.6e/12bitADU and x16 to get to 16bit data), so the excess signal is 0.7-1.5 electrons, which corresponds to a dark current of 0.002-0.004 e/s/pix (very low).
Assuming shot noise, the total noise (read noise and dark noise) should have been ~2.5eRMS and it was measured to be ~2.3eRMS - the good agreement means that there is no fixed pattern noise (FPN) in the centre of the field.
In the brightest part of the "amp glow", the excess signal above bias is ~70 ADU or 7 electrons, which corresponds to a dark current of 0.02e/s/pix - still very low.
Again assuming shot noise, the (dark noise and read noise) should have been ~3.3eRMS, but I measured ~4eRMS - so there is a little bit of FPN in the "amp glow" region (it can be seen at extreme stretch).
ie, even in the worst glow region, the total camera noise from the 1600 is still way below the (dark noise and read noise) of most CCDs and in the central region it is almost non-existent.

The fact that the "amp glow" can be seen at all is an indication of just how low the noise in this chip really is - in any CCD, this level of glow would be submerged below the combined dark noise and read noise. So, you can dark-calibrate out the "amp glow" if you wish and it should not add any noticeable noise to your images. Alternatively, you could dither to break up the FPN and then ignore both the "amp glow" and dark calibration altogether and rely on non-linear rejection to remove any abnormal brighter pixels - you might find this to be as effective as full calibration for broadband imaging and possibly also for NB imaging under moonlit sky.