RE: [ATM] UPS Modified Scope

["ATM_Wes" <atm_wes@sbcglobal.net>]

If insurance is covering it. Why not contact Meade for an OEM replacement?

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
Jay Kirkland
Sent: Thursday, September 02, 2004 6:05 PM
To: atm@atmlist.net
Subject: [ATM] UPS Modified Scope

	That is a total horror story. 
	If insurance pays for it, I'd go with a spider from Gary Wolanski.
I've found the quality of his products to be first rate. ProtoStar makes
beautiful spiders but despite what their web page would have you believe,
they are not easy to install at all. Your installation (the holes you drill
in the tube) must be pretty much exact from the first moment as there is
virtually no latitude for adjustment. And their install instructions don't
take into account varying thickness between one  secondary and another. Do
note that Mr. Wolanski's 4 vane spiders have offset vanes and that you
cannot use holes placed at 90 degree intervals around the tube. So you'll
have to drill 4 new holes in your tube. 
	If you need stainless, any good model shop sells stainless steel in
varying thicknesses and widths. I wouldn't cut it into a taper or cut along
its length at all, as that will always roughen the edge and create a thicker
vane than you'd want.
	It is however extremely easy to make spiders using guitar string
stainless wire. I used one on my 12 1/2 f6 for years, switched back to my
Novack spider to see what that would be like, was horrified at the
diffraction spikes that I wasn't used to seeing, and quickly switched back
to wire. I used .25mm/.010in on the 12" and .51mm/.020in on my 20". The 12"
spider may be a little fragile (especially as temps here vary  over the year
between -30 F and +90F, the best seeing aways being the former) , and the
spider on the 20" is actually overkill. Mel Bartel's design for a wire
spider seems really complicated to me. I followed the style in Paul's
Telescopes for Stargazing, pg 118. You do need a couple extra inches of tube
at the eyepiece end for that design, tho. Made of a couple small wooden
circles, some 1/4" dowel, and some screw eyes, is all. Doesn't look like
anything remotely professional but once you get used to observing w/o
diffraction spikes or diffraction spread all over everything (see curved
spiders), you'll never go back. Good luck. 

Jay


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