Re: New AP scope and more

From: Bill McHale (wmchal1_at_umbc.edu)
Date: 10/29/04 

Date: 29 Oct 2004 06:44:55 -0700

chris1011@aol.com (Chris1011) wrote in message news:<20041028180003.28581.00002210@mb-m20.aol.com>...
> >>Maybe one day we will have some type of glass to make a color free achro
> doublet.>>
>
> It's called Fluorite and when coupled to a Schott N-KzFs2, it will produce what
> you want - pretty well color free doublet.
>
> Fluorite costs about $1000 per kg in raw form. A 9" blank would weigh about
> 4.5kg.
> The Schott mating element will cost about $1500 to $2000 in raw form.
>
> Then comes grinding, polishing, figuring, anti-reflection coating (at ~$400 per
> surface), mounting in cell, making the tube assembly with focuser, dewcap,
> baffles, etc. Some profit for the telescope maker, some money for national,
> state and local taxes, a bit of overhead, etc etc etc. Where do you think this
> will come in at, comfortably?
>

Roland,
What was the glass you used in your older Doublets? I had a Star-12
and it was a lovely scope, only sold it when I got my 130. While the
130 was a step up, the Star-12 was a great scope with virtually no in
focus color visible even on the brightest objects. 

--
Bill