I'm on the cusp of, I think, maybe finally getting a PVS-7 for NV use with my 85mm refractor.
To this end, I'm starting to buy in the accessories I would need to use it in prime focal mode, where I remove the existing objective lens housing, screw in the C-mount adapter, and then attach either a 1.25" or 2" nosepiece for use straight through in my star diagonal.
Question is, should I be viewing in prime mode with a 1.25" nose/barrel or a 2"? My star diagonal is 2", but I also have the 1.25" adapter for it.
Normally I would go with 2" and not think twice, except for the fact that I know that NV requires all manner of very expensive H-alpha filters to get the most out of it, such as the Chroma line of filters (3nm or 7nm). However, these filters are really expensive, and the 2" filters are nearly double the cost of the 1.25" filters. So given the cost of the filters, I would rather go with 1.25" just to save some money, but are there substantial advantages for 2" when using the PVS-7? Does the PVS-7 have enough aperature in the tube to even fully utilise the full 2" barrel?
I suppose going with 2" filters would also allow me to someday use a 2" Ethos eyepiece (with the filter), and attach the PVS-7 afocal to that eyepiece, for crazy wide-field views?