Re: [ATM] Blank question

[Andy Saulietis <iss@pvtnetworks.net>]

Bob May writes,

>Yeppie, one of the things that people often don't figure in when they want a
>big scope is the minimum magnification that is required to get the full
>aperture to the eye. <snip>


True, the larger the aperture the more mag is needed to
make the exit pupil smaller than the eye.

However, even at 1M aperture, at normal (minimum) mag
you can still get a real field of >0.5 deg, for example
using the 31MM nagler, the real fov is ~0.56 deg.
The focal length has to be ~f4.6 at this combination,
or a Barlow used to match the required efl.

A friend of mine regularly used the McDonald 107"
visually, at the nomal mag of ~428x..the fov is
<1/4 deg but he says most planetaries show color
at this aperture..:)



Andy Saulietis
ISS Enterprises
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