In a message dated 3/17/2004 4:31:20 AM Eastern Standard Time,
FaltusR@xxxxxxxxx writes:
> Hi,
> does anybody have extra telescope adapter for OM?
> For example Vivitar made this.
> For those of you who use it: What is
> binocular equivalent magnification when i
> attach it with 200mm objective?
Hi Radek,
I don't have an extra one, but they are still readily available. Try
www.telescope.com. The one I have comes in 3 pieces: a short tube that fits in
the
telescope's focuser and has a standard T thread on the other end, an OM T
adapter, and a third piece with T threads at each end which can be inserted
between
the first two and holds an eyepiece for eyepiece projection work.
The magnification depends on the focal length of the telescope. I assume
you're refering to a 200mm aperture 'scope. If it's a Newtonian/Dobsonian, it's
probably about f/5 or f/6, giving a focal length of around 1000mm - 1200mm.
Compared to a 50mm standard lens, that's a magnification of 20x-24x. If you've
got
an f/10 Schmidt-Cassegrain, the focal length is about 2000mm, and your
magnification compared to a 50mm lens is about 40x. You can get greater
magnification using the eyepiece projection technique.
A good source of information on astrophotography is the book Astrophotography
for the Amateur, by Michael Covington (a former Olympus list member).
Hope this helps,
Paul Schings
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