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Why So Few 90-110mm F/7-F/8 Doublet Refractors??

Started by jkurtz555, 03/27/2006 10:40AM
Posted 03/27/2006 10:40AM Opening Post
It seems the "sweet spot" for reasonably priced, higher performing doublet achromats (ED glass) seems to be 80mm in F/5-F/7 focal lenghts...does the boost in aperture add so much chromatic abberation or added glass cost that all we're ever going to see is a never ending supply of 80mm scopes (in a never ending array of colors). There's got to be a substantial number of 80mm owners who are ready to move up to something a bit larger.
Posted 03/27/2006 05:56PM #1
For whatever reasons Chinese manufacturing seems geared to
high-volume mass production. And I think the sweet spot for
that is in the 80mm scopes. That said, Orion does have the
ED100, and larger Meade scopes are supposedly on the way.

I expect the reasons for the lack of larger scopes has less to
do with chromatic aberration, and more to do with the
market and US importers willing (or not) to take the chance on
ordering 100 (or 500) of some newly designed Chinese high-end
scope. I think the Chinese are up to the task, and the
laws of optics are favorable.