On Mon, 14 Jul 2003 15:37:51 +0200, "Steven Van Impe"
wrote:

Hello everybody,


I recently collected some lenses of various origin (a cheap binocular, a
cheap wide-angle photographic lens, and a powerful magnifying glass) and was
thinking about what I could do with it. I'm thinking about building a rich
field telescope for watching large OCs (my favourite objects) and also to
help out a friend who wants to try out some theories about observing meteors
through a telescope.

I've googled for some helpful hints, but there aren't many detailed pages on
rich fields, and most of them are Newtonians. Has anyone tried this? Does
anybody have a link, or a book reference? Thanks in advance !

Secondly: I also have a broken laser printer. I vaguely recall reading about
something useful that could be done with such an item, but I can't remember
if it was lenses or something else. Does anybody have a clue as to what I
might be talking about? Coz I don't :-/


Clear skies!

Steven


Don't waste your time with old camera lenses. Most of them have very
little true aperture (eg. 300mm f4.5 true aperture is only 67mm).
Also, even using them at low power they tend to produce poor images,
especially at the edge with simple eyepieces. Magnifying glasses
won't work at all because they aren't achromatized. Binocular lenses
are usable, but why would you want to go from two to one eye? Plus,
bino lenses (cheap ones) are not that accurately made and don't
support magnification well.
You can buy an 80mm f5 or so achromat for about $50 and cobble
together a rich field scope that will actually work for your intended
use.
-Rich