Dear fellow astronomers,
I use my ASI294MC pro with a ZWO filter drawer mounted directly against the camera body to minimize the distance between the sensor and my l-ultimate filter. That works well. I never had one single halo.
It appears that the locker screw for the filter drawer was indeed not (it never was so far) firmly locked and scratched the case of my camera.
Question : does anyone has confirmation that the case is made of aluminium and is not subject to rust ?
The case is not reacting to magnet. It also looks like aluminium. However, in the absence of such a confirmation, I will take actions to protect the area (antirust primer covered with tape).
Many thanks and clear skies !