Re: ATM Refractor Baffles & Homemade Star Diagonal

["B. Pepin" <atmjedit@conceptsnet.com>]

Hi Dennis,

Yes, please add baffles, at least at the tailpiece before the focuser. Check
any number of sources for tips on construction and placement, including the
archives here. Sam Brown's All About Telescopes (Edmund Scientific) shows an
easy method for scaling out the tube for baffles, also Richard Berry's Build
Your Own Telescope.

Star diagonal needs to reflect light squarely perpendicular, with the best
prism or mirror you can find. Small Newtonian diagonal mirrors are readily
available, or make a flat to the size you need. ABS plastic pipe fittings
make a good housing -- Tee fittings in 1.25 - 2,0-inch size work well, and
can be trimmed to shaped with a saw and fitted with a section of
1.25-inch-to-2.0-inch chromed or brass drain pipe to go into your focuser,
and a 1.25-inch-to 2.0-inch I.D. section of slotted brass pipe (or heavy
[schedule 40 at least] PVC, tapped for knurled NYLON set-screws), to hold
the eyepiece.



----- Original Message -----
From: Dennis Woos <wooscons@sover.net>
To: ATM List <atm@shore.net>
Sent: Thursday, December 07, 2000 1:00 PM
Subject: ATM Refractor Baffles & Homemade Star Diagonal


>
> I am building a 75mm f/4 refractor, and would like some advice about
> whether or not to add baffles to my tube.  I have mounted the lens in a
> homemade 3/4" plywood cell, and it fits into a 3 1/2" tube.  All inside
> surfaces are painted flat black.  Should I add baffles?  Does the Orion
> 80mm short tube have baffles?  Is there software like Newt to compute
> the baffle sizes for refractors?  And finally, any tips on constructing
> a star diagonal?  Thanks.
>
> Dennis
>
>