Re: Joel's Christmas list

[Brian Reynolds <reynolds@xxxxxxxxx>]

Greg wrote:
>
> Here's something Joel needs for his Pentax 67.
> (He would have to get a second one later for
> simultaneous hypers).
> 
> Ebay Item #35976180
> Pentax 800mm f4 lens for 6x7
> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=35976180
> 
>   I saw one of these last summer. The front
> element is as big as a pie plate!
> 
>   I wanna see the slidebar it would take
> to hold two of these babies :)
> 

It would be a lot cheaper to buy a 8 inch telescope mirror grinding
kit and telescope making book and build a pair of 8 inch Newtonian
binoculars.  Just mount the pair of Pentax 67s to the focusers instead
of eyepieces.  Willmann-Bell's kit comes with two pyrex blanks, and if
you use a plaster/tile tool instead of one of the pyrex blanks you'll
wind up with two mirrors.  It would probably even be cheaper to pay
someone to build you a pair of 8 inch Newtonian binoculars than to buy
a pair of these lenses.

It would probably be easier (and still cheaper) to buy a pair of
Tele-Vue TV-101s.  Of course they are only 540mm (focal lengeth)
f/5.4.  There's at least one astrophotographer on the net who has a
pair of these on the same mount (one for MF astrophotography, the
other as a guide scope).

-- 
Brian Reynolds     | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx | "Oooh!"
NAR# 54438         |    -- Dexter and Dee Dee
                   |       "Dexter's Laboratory"