Quote:
Originally Posted by PlanetMan
I probably misread the article but it doesn't actually discuss fluorite in refractor optics - I thought the whole idea of fluorite particle lens (ie FPL 51 53) was to get the good benefits of fluorite crystal without the hiccups (fragile, brittle, expensive, toxic etc)
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No, it wasn't specifically mentioned - just about the discovery of fluorine origins... which I branched off on. ANYWAY...
FPL53 only has roughly 20% (MAXIMUM) or fluorite in it, so it only proffers SOME of the good Fl characteristics. FPL53 still shows significantly more light scatter than a CaF2 element does. I haven't looked at O'Hara's site for a while, but I think FPL51 - the most common glass in Chinese refractors - only contains roughly 4 to 8% fluorite.
I found this iStar forum thread of interest:
http://istarscopeclub.proboards.com/...-fluorite-apos
Well worth the read if you are interested in the differences between CaF2, FPL51 and FPL53 glasses.
Andrew - I make all my vodka shot glasses out of CaF2 - slamming them on the table or setting Ouzo alight is guaranteed to shatter them into non-reusable status
