Hi folks,

I'm catching up (again) on an e-mail backlog. Two items came up
a few days ago that I should have addressed: viewing the lunar farside,
and using Guide with Mel Bartels' SCOPE.EXE.

Roger Curry mentioned attempting to view the lunar farside by setting
an altitude of 400 000 km. Problem with this is that it causes you to
get the "viewpoint" of someone standing on a 400 000-km high mountain.
Set that altitude and look back at the earth, and you will see (in
Roger's case) Jacksonville, Florida, squarely at the center of the
visible disk of the earth (move the cursor over that spot, and the
alt/az readout will show that you're looking at the nadir.)

Start animating, and Jacksonville will stay at the nadir and at
the center of the earth's visible disk (after all, you're still "in"
Jacksonville, albeit very far above it.) Once every 25 hours or so,
you will flash by the moon at very high speed, sometimes just barely
above it. (At its maximum northerly location, the moon does not
quite pass over Jacksonville.)

Masaki Kouda's suggestion of viewing the moon from the Sun (or
Venus or Mercury) is one way around this. Another is to set your
viewpoint to be on the moon, longitude 180, latitude 0, altitude
92 000 km. Then look back at the moon. There is some discussion
of this bit of trickery at

http://www.projectpluto.com/interest.htm#lagrange

Bernard Heathcote asked about having Guide, when used with Mel
Bartels' SCOPE.EXE, supply a moving cross indicating the position
of the telescope. Guide does do this for encoder-based systems.
I dunno how well it would work with SCOPE.EXE, though. SCOPE
and (DOS) Guide have to run essentially one at a time. While Guide
is running, the telescope can't be moving. Then you switch back
to SCOPE, tell it to slew, switch back to Guide, and it centers
on the new telescope location. (Or you click on "Slew Scope" in
Guide, and SCOPE picks up that RA/dec and moves there.) Or am I
misunderstanding what you're trying to do here?

Scope control in Guide is, in general, not what it ought to be.
About the best that can be said for it is that I've learned how it
should _not_ be done. However, I recently got a little ETX-70
Autostar, very convenient for testing purposes. Using this, I hope
to make scope control in general (not just for Meade scopes) much
less user-abusive.

-- Bill