ZWO ASI461MM-Pro challenge with sensor analysis

[kellygrant]

Hello all,

We are attempting to use SharpCap Pro's sensor analysis to characterize an ASI461MM-Pro mounted to a PlaneWave CDK14 at the University of Oregon's Pine Mountain Observatory, which seemed smarter than reinventing the wheel with custom coding/scripts. Unfortunately, when the analysis reaches high gains and correspondingly short exposures (typically in the 0.5-0.6ms range), we are getting banding across the image. This is likely due to the rolling shutter in use by this camera, combined with an older AC-powered LED flat panel that is flickering, and resulted in the initial sensor analysis indicating a shocking 29% linearity.

We have tried selecting a narrow/long vertical area to analyze, since the bands run horizontally. This made little difference, with the sensor analysis results indicating a mere 30.7% linearity. I suspect the issue is with the flat panel and not with the sensor, since normal lights/flats/darks seem to be fine.

Is there any way to adjust the sensor analysis scripting so that it doesn't extend all the way to this extreme gain and exceptionally short exposure times? That seems like it could work around this issue. Or would that fail to appropriately/fully characterize the system?

I suppose we could use natural light as the source, but since that constantly varies, I am not excited about the accuracy we might get from that approach. We could also purchase a non-flickering flat panel, of course, but department budgets are tight these days, so that is another less-than-optimal approach.

Thanks much for any advice or assistance!
Kelly Grant