Quote:
Originally Posted by The_bluester
I don't think that it is safe to say that because companies advertise "FPL-53" and not "S-FPL-53" the glass is not the real thing. My own Stellarvue advertise FPL53 (And who would go to the bother of extensive hand figuring of cheaper alternative glass to sell in quite expensive "Premium" refractors that people are bound to performance test?) and a quick search took me to a page on an Explore Scientific scope advertising an "Ohara FPL-53" element with a direct link to the S-FPL-53 spec PDF on the Ohara website.
You would probably be wary of a Chinese made scope at a very competitive price that just says "ED" glass though.
|
But have a read on the Stellarvue site about optics and you will read Vic's story how they are experimenting with other glasses and that they feel a number are equivalent to fpl53 (for aperture 130 and less) and they will be gradually moving to fcd100... starting with their svx130t... they have stocks of fpl53 they will use up and use that for larger lenses until Vic is confident it is equivalent. The core of the argument is that the strehl is more important than the glass type.