This is done by C5/Cheapy-ERF/PST etalon/BF10.
The PST etalon is really very well designed, the afocal lens system does a great job in maintain the incoming cone to become parallel before feeding into the etalon. That maintains the bandwidth very very well, and also produce a very temperature stable system, since light are diverged to become parallel before the focal point, that helps a lot to reduce the heat reaching the etalon, I believe. For the case of a C5, light from 127mm is converged into a 15mm light cone, which is not too hot. If I put my hand at the focal point of the C5 after the Cheapy-ERF, I can feel the intense heat after 10-15s, however, since the bandwidth is well kept, I suppose the heat reaching the etalon should be way less, otherwise, bandwidth will be widen before the etalon breaks for the intense heat.
Enough said, time to show the pictures:
C5 2x Cheapy-ERF:
C5 + Cheapy-ERF at prime focus, this is the first clip processed by Registax V4 with 2 alignment points, no need to convert by VirtualDub any more, save a lot of disk access and disk space:-
Prominence merged with surface detail:-
Prominences from all part of the disc:-