Hello Does ST-402 have a window or a filter in front of sensor? If yes, how much is thickness? I'm using ST-402 to do spectroscopy by combining with our own grating. However, obtained spectra had a periodic signal which looks like an interference pattern caused by a thin window. So, I'm wondering if ST-402 has a window or a filter. Akira
Doug would know more I, from the drawings I inspected tonight the chamber window should be 3mm thick. The glass over the CCD is "0.060