Dear all,
Be prepared to move up larger aperture to 8inch plus for Ha solar and DSO Ha imaging. Yes, dual purpose scope.
A genius method to di-electrically coat the front corrector to achieve big ERF at 1/4 lambda.
At present the biggest ERFs are 180mm by Baader D-ERF (1/10 lamda) and up to rarely made 10 inch by Daystar (1/4 lambda).
http://www.airylab.fr/AirylabUS/index.p ... &Itemid=67
Not cheap and you have to add up Etalon and blocking filter.
Raymond