Well with all the poor weather we have been having this summer, and real lack of opportunity to get any imaging / observing in I decided following seeing the patent drawings to take a look at how the PST etalon assembly was made. For some time now I have thought that misalignment of the etalon within its housing is the likely cause of uneven illumination and bandpass across the field of view when in use, and looking inside at the rubber compression system that tunes the etalon my thoughts were reinforced.
This video shows how to disassemble and reassemble a PST etalon housing - usual rules apply - don't blame me if it goes wrong for you!
