Recently Fixed Camera Not Working

I did not say that the bright star recognition problem is directly related; however this is still an error that must be fixed, as it impacts a bunch of calculations.

If you have not enabled Auto Dark substraction on the guider, it is harder to separate the star from the background. So I would recommend checking if this is enabled.
With the STX Guider, it has a dark shutter which can be used for this purpose.
There is an approximate Signal to Noise ratio that is used to separate the star from the background noise (eg dark current, hot pixels).
The SNR may be too low due to the bright background.
0.02s would allow in ideal conditions 50Hz update rate (the system can't do it, the hardware can't move that fast).
0.1s would allow 10Hz update rate in ideal conditions.
So perhaps just bump up your exposure time.

Calculations around star magnitude are used in some places in MaxIm, for example, in the information window.

For it to know distances to send to the mount or timing for guide pulses, it requires parameters such as pixel size which it gets automatically from the camera, and from the optical parameters, which are not usually available automatically.

MaxIm will log errors. For example, if you View.. Log Window, and had a look you would likely see something like this:
02:38:31$5 Warning - Error getting guider imageError -
Error computing arc seconds per pixel
Focal length invalid or inaccessible

Does that help?

BTW the window going mostly white is a version 7 issue we're aware of and plan to fix in an upcoming release.