[AG Hybrid (Adrian)]

Originally Posted by Hans Tucker

I had to go looking and found a suggestion of Televues uses of Lanthanum here:
http://www.televue.com/engine/TV3b_p...d=78#.VJqRRA8Y

And I found other websites that state that Lanthanum was used in the Panoptics and Radian eyepieces.

Well how 'bout that? "The finest performance requires the finest materials such as high index lanthanum and fluorite type glasses, in some cases costing up to 15x more than ordinary glass types."
I suppose FPL designated glass would be considered Fluorite type glass.