This image of the Moon was obtained on JD 2455849.
Notice the strong saturation at the lower left corner – on the sky! Other parts of the Moon are safely exposed in the 10000-30000 counts range.
Here is a supposed ‘dark’ frame showing something similar:
Most of the dark frame is at the bias level of 397 – the corner shoots into 65000!
This was during our ‘everything looks like a bias frame we think something is getting stuck’-period.
Both frames above are available in the BADEXAMPLES/ directory as FITS files.
