Re: [ATM] Width of Dome Slit?

["Bob May" <bobmay@nethere.com>]

Not too sure where you're going with the math.  I'd look at it as
an angle problem.  Considering that the FOV is probably 50mm wide
at the focal plane and that the scope is an F10 then the scope
will have a focal length of about 3500mm.  This means that every
3.5m you need to have a larger diameter of 50mm in order not to
vignette the FOV.  If the scope is 3.5m from the dome, that means
that the dome opening needs to be at least 400mm wide and since
2x aperture at the opening is what you want, that means that you
need an opening 800mm wide.  If you can turn the dome 180 degrees
in less than 4 minutes, then you are fine as that is 1 degree of
rotation of the sky and if you start the turning 0.5 deg. before
the scope hits zenith, the rotation will conclude when the scope
is the same distance past zenith and at no point will the beam
from the scope get more than 25mm from the center of the opening.
Next is that when you mount the mount in the dome, you want to
offset it so that the scope, when pointing straight up, points up
the center of the dome.  Not doing this offset just means that
the dome opening needs to go that much more over the top of the
dome but that distance won't be all that much.
Hope this makes things clear to you.
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
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