Nye Optical f1.4 / 150mm UV-VIS-IR mirror lens

[Ron Scubadiver]

It seemed at one time mirror lenses were everywhere, then they nearly disappeared.

[Akira]

1) to form a very stable substrate, regarding very low thermal expansion, for both mirrors
2) to form a very hard and resistant, yet very transparent (UV-IR) overcoating for thr aluminum first surface mirrors

Klaus, thanks for further info on the quartz material.  Apparently this mirror lens would not be used under the temperature of 700-1200 degree, the character of the low thermal expansion should be reliable enough for the purpose. 

[Dr Klaus Schmitt]

Klaus, thanks for further info on the quartz material.  Apparently this mirror lens would not be used under the temperature of 700-1200 degree, the character of the low thermal expansion should be reliable enough for the purpose. 

That's not the point Akira: it is about thermal changes of the mirror which leads to variations in focal length(s) of the two mirrors and on very large mirrors, aöso distortions, so if you use it at room temparatures and you take it outside at say zero degrees, this change in temparature may lead to that.

[Akira]

That's not the point Akira: it is about thermal changes of the mirror which leads to variations in focal length(s) of the two mirrors and on very large mirrors, aöso distortions, so if you use it at room temparatures and you take it outside at say zero degrees, this change in temparature may lead to that.

You mean, the quartz is more stable than the conventional optical glass in the environmental temperature changes?  I'm well aware that the ED or fluoride glasses are very much affected by the temperature changes, which is why the lenses that uses ED glasses are made to focus past infinity to compensate for that.

[Dr Klaus Schmitt]

Yes, exactly Akira!

[Akira]

Yes, exactly Akira!

Thanks!  Now it is clear!

[Alaun]

Klaus, the thermal expansion coefficient of quartz (crystal) is more than 10 times lager than that of quartz glass.

[Frank Fremerey]

Klaus, the thermal expansion coefficient of quartz (crystal) is more than 10 times lager than that of quartz glass.

Danke. Ich liebe solche Beiträge!
Thanks. I love this kind of Intervention.

[Akira]

Klaus, the thermal expansion coefficient of quartz (crystal) is more than 10 times lager than that of quartz glass.

Hmm...so, what's the purpose of using real quartz?

[Tristin]

When do we get to see the images?1?   

[Dr Klaus Schmitt]

When I'm back in Germany 

[bikersgold]

What is one of these lenses worth?

[Dr Klaus Schmitt]

What is one of these lenses worth?

Why, have one for sale??