Really seems to be a nice piece of glass ;-) I'm going to assembly all the pieces i've collected to do my stage 1 mod, i write about it on the italian Astrofili forum too.

Thank you for reply Antonello :-D I've read all your posts, here and in the others forum, I appreciate very much your tests about photografic filters, too bad it's too late for saving my money because after a week without answer I've bought a Baader Erf filter...

Ah, ok.. I've read your other reply about the heat issue that change the tuning or etalon. Now all is clear, I need a full aperture Erf :-D

Great ;-)

Beautyful setup! You've done a nice job, wich kind of ERF have you mounted?

Thank you for reply Mark! Do you think that the default cofiguration of PST with anything between the achromat and the black box isn't enough safe? I'm confused... i'm planning to change the 40mm achro with a 70mm achro (both f10) putting and additional filter that cut the IR, about filtering nothin...

My name is Alex and I'm new in this Wonderful Forum :bow I live in the Mugello Valley, near the Appennini north of Florence, Italy, I love astronomy since I was eight year old. I'm going to make my first Pst Mod, stage 1 , i'm planning to add a 70 or 80mm f10 acro WITHOUT FRONTAL ERF to the black bo...

Very very nice solution!
What do you think about a "Sunlux" without the frontal ERF , on a stage 1 PST mod, with a second generation PST that have its internal Erf without filter on the original 40mm lens?