>>I can center a star on the crosshairs at 300X and have the image stay put
>> for 30 minutes, far longer than I need for unguided CCD work!

> 30 minutes! I must be doing something terribly wrong. With the LX200 10",
> Pictor 416xt and superwedge, the best I've been able to get is a few
> minutes, and that's after four alignments..

I spent a ridiculous amount of time fiddling with my polar alignment. I
tried the Meade precision alignment procedure, then I drift-aligned, and
then I did the whole thing over... about 20 times. I was checking things out
again last night. I centered Rigel on the crosshairs, went inside for 20
minutes, and then checked. I was still within less than 1/2 of Rigel's disk
using a 9mm eyepiece. You need a really good wedge, I use a Milburn wedge,
and a lot of patience. Unfortunately, I seem to be getting obsessed with
this. It's just that I hate guiding!

In any case, the theoretical pointing accuracy is 6", but you're not
going to get this except by sheerest accident. However, you should certainly
be able to get excellent tracking; the drive is crystal-controlled
after all. You will encounter problems with flexure after some period of time,
and possible mirror shift, and atmospheric refraction effects, and who knows
what else. Don't forget to do the PEC training stuff; that can remove several
minutes of periodic error. If you want to check drift ignoring the PEC, set
up your target star and then check it every 8 minutes; that's the period of
the worm gear.

______________________________
| Bill Ezell |
| http://www.duckpond.mv.com |
------------------------------

The box said 'Win95, NT, or better', so I used Linux

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