Quote:
Originally Posted by Peter Ward
The Lunt 80mm is hard to go past in terms of bang for buck....that said, all of their pressure tuned etalons can suffer from "hot spots" that, particularly if imaging is your goal, can give uneven illumination to full disk images.
Well tuned, a front etalon 90mm system can deliver this sort of image
A front mounted etalon on the telescope of your choice will deliver the most consistent field illumination, but the rub is that is your most costly option.
I would not go under 60mm in aperture. 90mm is a "sweet spot" that balanced resolution/seeing/cost, unfortunately Lunt don't make a 90mm etalon...I covet their 100mm etalons...but only you can decide whether that or their 60mm will fit the bill.
P.S.
For correctness I should also point I am a Lunt Dealer, but use original Coronado (read pre-Meade) filters (made at the time by Andy Lunt's dad  ) |
Thanks Peter comes down to cost and how much use I'll get
So probably be a toss up between the 60 or 80 Lunt as much as we all want the biggest and best .