On Sun, 22 Feb 2004 09:37:58 -0500, starman wrote:

You would essentially be limited to what Galileo used centuries later, a
very basic refractor telescope using one convex objective lens, perhaps
an inch (25mm) in diameter and a smaller concave eyepiece lens located
at the focal length of the objective...

That's not what I'd build if I were dropped into that period of history. I'd
make a Newtonian reflector. It would be quite practical to build one 4-6 inches
in aperture using commonly available materials. The quality of the glass can be
much lower with a reflecting telescope, and there is less glass grinding
required. The only lens would be the ocular- much smaller than a refractive
objective.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com