Hi all:
I just had my machinist make an adapter to allow me to turn my long Oly
lenses into a telescope. It uses a bayonet scavenged from a cheap 2x
teleconverter, and has a 1.25" hole with nylon locking screw on the
opposite end for holding eyepieces. I tested it for the first time last
night with a 300/4.5 and 500/8, both with and without 2x-A and 25mm
extension tube. Things I found:
1) The 500/8 with or without the 2x-A is sharp and free of color
fringing. Probably better than most telescopes you can buy in this
range.
2) The 300/4.5 showed some color fringing, but it was not
excessive. The 300/4.5 did seem even sharper, and was of course more
contrasty than the 500/8 due to the lack of a central obstruction (fancy
talk for secondary mirror :).
The moon looked wonderful, and I could see M3, M81 & M82, and M42 no
problem.
With a 7.4mm eyepiece and the 2x-A, the 500/8 (which is effectively a
1000/16) 135x, which is about the limit for this diameter objective (the
general rule is 60x/inch of aperture, which for the 500/8 is about
148x). I'd love to try one of those short focus Nagler's, though.
Mebbie at Stellafane.
I'll be taking this with me to Cape Hatteras this week to use as a
spotting scope. I'll let you know how it turns out!
Cheers,
--Lee
________________________________________________________________________
R. Lee Hawkins lhawkins@xxxxxxxxxxxxxxxxxxx
Department of Astronomy lhawkins@xxxxxxxxxxxxx
Whitin Observatory http://www.astro.wellesley.edu/lhawkins/lee.html
Wellesley College Ph. 781-283-2708
Wellesley, MA 02181 FAX 781-283-3667
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