Re: APO GOTO Polar and Star alignment

Chuck Hancock


My experience with the 400GTO, so far, is meager. Just the same, here
is what I can tell you:

1. There is an altitude adjustment screw that increases latitude.
However, I haven't found anything that can lower altitude besides
loosening the "main bolt" and lowering manually. This seems
rather coarse. Have I got this right?
The same knob increases the altitude and decreases it. I have found
that you can loosen the "main bolt", the one with the large Allen cap
head, just a little loose, and then proceed with the polar alignment.
You can adjust the mount up and down in altitude (latitude) with the
hand knob on the South end of the mount. I see no harm in leaving the
main bolt a little loose, at least in my experience. You are supposed
to retighten it after you are polar aligned, though.

enough <g>) describes several methods of polar/star alignment. What
is the best way of re-calibrating the scope, after you have polar
aligned if you accidentally move it manually? Is there a one-star
type of alignment?
I have had a to do a massive re-alignment when, a couple of times, the
scope wanted to slew to the completely wrong area of the sky. I assumed
I did something wrong, such as recalibrating in error or moving the
scope manually, although I wasn't sure exactly. Anyway, in such an
instance, I simply motor-slewed to the nearest "name" star, and then
proceeded to recalibrate on that one. All was well again after a
correct recal. As long as the alt and az adjustments aren't moved, and
the tripod remains undisturbed, the polar alignment will be exactly the
same. It's just a matter of re-orienting the mount's brain.

3. Most of my GOTO experience has been with an LX-200 which has a
built-in feature called "high precision pointing". When you
GOTO an object with high precision pointing turned on, the system
goes, instead, to the "bright star" nearest your target. That star
flexure, mirror flop, or aren't perfectly polar aligned. Is there
any equivalent to this in AP GOTO? Of course, you could recalibrate
manually with any GOTO mount by finding a star etc, but it really
saves time to have the software lead you through this automatically.
You will have to coax the 400GTO through this type of routine yourself
by choosing a nearby star and recalibrating. There are a vast number of
name stars on the 400GTO rom, as well as a catalog of stars by Bayer
designation (Greek letter and constellation). For the Greek, got to the
objects/tours/stars by constellation menu. I find this list more useful
than the name stars at times. I haven't exactly memorized *all* the
names yet, and the Bayer designations are easier to look up in my
handiest of atlases, the Cambridge Star Atlas.

I hope this helps.

Best regards,
Chuck Hancock

c d h 5 9 at b e l l s o u t h d o t n e t

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