I had the Orion version of the 80mm f/5 refractor and sold it after only
two attempts to use it. I bought it as a spotting scope. Since it's a
simple achromat and not a telephoto design the optical path is very
long. It's fine as a richest-field astro scope on an equatorial mount
but I found it a bit clumsy to use as a spotting scope. As a camera
lens it grew much worse since the tripod mounting block position is
fixed and does not allow for the imbalance of adding the camera. I
simply found it unusable as a spotting scope or as a lens based on
length and balance. That's why I was coveting the 500mm f5.6 mirror
lens since it's only 7 inches long... but then there's the contrast
question. Can't win on the cheap I guess.
Note to Jim: If you're losing the metering capability of your camera
after attaching a T-mount something is wrong with your T-mount. The
meter should work fine.
Chuck Norcutt
Woburn, Massachusetts, USA
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You can buy a Celestron/Eagle Optics 80mmWA refreactor that can also be
used as
a 400mm f/5 telephoto lens. The objective lens is 80mm in diameter,
while the
photgraphic speed is f/5. This gives a focal length of 400mmm. It comes
with an
equatorial mount, star diagonal, and eyepiece for around $230.
The major disadvantage is that you need to use the scope with an Olympus
mount
T-Adaptor. The T-Adaptor fits on your camera and then screws into the
drawtube
of the scope. This means you lose the metering capability of your
camera.
Still, it's a reasonabley fast lens and very sharp.
jim mueller
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