I’ve just had an unexpected occurrence with my Pierro Astro Atmospheric Dispersion Corrector (ADC) after imaging Venus in the heat today. I removed the camera before parking my mount and the ADC spectrum glass at the camera end fell out (luckily I have rubber flooring in the observatory in anticipation of occasional mishaps).
Pierro Astro are a small French company and they are all away on their August holiday at the moment, so there is no one available to contact about this. I have been able to pop the glass back in and grip it with the arm that holds it in place for adjustments but I now don’t know if the spectrum glass is correctly oriented – or the right way up if there is a right way up!
Does anyone happen to know if it matters which way round the spectrum glass is placed or if it has to be a specific orientation before being re-attached? It can be rotated easily through 360 degrees until the arm is tightened, when it is limited to the movement of the arm (about 90 degrees).