Hi Edward,

1. I notice that most of the GT scopes on fork mounts have both 3
star and 2 star alignment modes. The ones on a German Equatorial
mount only have 2 star alignment modes. After thinking about this, I
think I know what the difference is. The two star modes assume that
you have already polar aligned the mount. This way, they only need
the 2 stars to determine where everything else is. Am I correct?

You are correct. Actually, if you have good polar alignment, you can do one
star alignment with many of them.

2. One disadvantage to longer focal length scopes seems to be the
difficulty in achieving LOW magnifications for deep sky observing.
For example, an 8 inch telescope with a 2550mm focal lengh and a 40mm
eyepiece is going to have a magnification in the low 60's while the
same aperature but a 1000mm focal lengh and a 20mm eyepiece is going
to give a 50x magnification. It is also harder to find the longer
focal lengh eyepieces (at least where I've been looking). People keep
talking about focal length reducers but I can't picture how this works
optically (I understand extenders). Can you point me to an
explaination of the reducers?

A reducer is a positive lens placed before the focal point. Often these are
used to flatten the field as well. It is different from the eyepiece in it's
placement. The objective forms an image of the object being observed. The
eyepiece is then used as a powerful magnifying glass to inspect this image.
With the reducer, it is placed well before the focal point.

3. You want to let your optics reach thermal equilibrium to get the
clearest image. However, refractors and SCT's sometimes (often?) need
protection against dew and one way of doing this is to slightly warm
the front lens. Doesn't this degrade the optical quality by
destroying the thermal equilibrium?

Somewhat, but not as much as the dew obliterates the image! :-)

What you want is to have the front lens or corrector just a tiny bit warmer
than the night air.

4. Planisphere's seem to have east and west reversed. Now this
bothers me because I'm used to glancing down and then up and have to
perform some mental gymnastics to reverse things in my head. Are they
all designed to be held above your head? Are any designed to be
looked down at (ok, this one is hardly new, just something that has
bothered me on and off since I was a kid)?

See http://skyandtelescope.com/howto/vis...ticle_75_1.asp for a
good explanation.

Thanks .

You're welcome. Hope this helps.

Chuck Taylor
Do you observe the moon?
Try the Lunar Observing Group
http://groups.yahoo.com/group/lunar-observing/
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Mark