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Re: [APML] Horsehead and Pleiades testshots with 6x9 camera/OAG and BRC



Bobby:

Wow, that 250 Tak looks like one great instrument!!!! Maybe I'll consider getting myself a retirement present along those lines next year. Once again, the large format photos are simply awesome with this instrument. Congrats!!

best wishes,

Glenn Shaw

Bobby Middleton wrote:

From: Glenn Shaw <gshaw@alaska.net>
>
> What, by the way, are the technical details of this 250 Takahashi
telescope?
> Obviously its a reflector of some sort, and I assume 250mm diameter
mirror?
> Pricey?

It's a Baker Ritchey-Chretian (sp?) FL= 1268 f ratio = 5 although t-stop is
probably at least f/6.5. It's got a field-of-view that will go to 6 x 9
field with little vignetting at the corners. The central ob is about 40%.
It's got a giant helical focuser built like a tank. Mine (and the early
production models) was made with a carbon fiber tube and so far I have not
needed to change the focus. But Takahashi quit using the carbon tubes in the
latter models. Takahashi claims 2 micron stars on axis. See:
http://www.buytelescopes.com/product.asp?t=&pid=1558&m=

> Pricey?
<vbg>
Bobby Middleton

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