On 27 Nov 2004 11:06:26 -0500, Allan Adler
wrote:


It was made in Japan according to the specifications of Meade. I didn't
see a date anywhere, but I know that it is at least 10 or 11 years old
and probably more.

Ok, newer import. But Meade supports their products pretty well, and
it might be possible to just buy a new drawtube, with the rack already
installed.

Is there any convenient way to try to figure out, without damaging the
telescope or screwing up its optical alignment, whether any lubrication
has migrated into the telescope tube? If it has, is there a good way to
clean up the mess inside? Maybe if I don't see any chromatic aberration
or haloes, or something like that, when I look at the sky, all is well,
but maybe the effects are subtler than that.

The biggest problem wouldn't be coating the lens, but causing shiny
places on the interior of the tube. It's generally noticable as a
loss of contrast, more when looking at a bright object, the moon for
example. If it's on the lens/mirror, it *may* cause haloes, or other
abberations, but chances of it getting there are pretty slim,
especially if the instrument hasn't been relubed with the wrong thing.

I clean, relube, recollumate my three reflectors about three times a
year, and there isn't too much you can do that isn't field adjustable
to correct. If it's a refractor, they're almost impossible to screw
up as long as you don't take the lens out of the cell. Once it comes
out, unless you mark everything to make sure it goes back in exactly
as it came out, all bets are off. Still, all it takes is marking so
you know what came out when. Especially the front and back faces of
the lens, in a non cemented lens, they can be reversed easily, and
then comes the bitch of trying to figure out which one is reversed. A
dot of water soluble marker can save hours of frustration.


I don't actually know that they are rivets. I only know that when I look
at the rack (not brass, by the way, but some grey metal), the brass things
I see holding it in place don't look like screws.

Could be a zinc alloy, not unheard of. Saves machining at the cost of
a longer life. If they were screws, the heads would be instantly seen
as such. Play in the rivets is also not unheard of, and sometimes can
be frustrating when you're trying to focus that 6mm eyepiece. The
higher the magnification, the worse small problems become. (Which is
probably why my favorite EP is a 28mm plossl.)