The pointing accuracy of the LX200 in AltAz is defined by how carefully
you center the two alignment stars. The pointing accuracy of the LX200
in polar mode is defined by how good your polar alignment is.

An error of a few arc minutes off Polaris can translate to a few degrees
near the celestial equator.

Just last night I spent about 2 hours refining my polar alignment on my
LX200. Instead if jumping right into the drift alignment method, I used
the LX200's built in alignment technique. If you follow these
instructions, you should be able to get your LX200 polar aligned close
enough that it will point as well as if it where carefully aligned in
AltAz and close enough to where you will see no Dec movement in 10
minutes of tracking.

1) Double check the LX200's time and date. The more accurate you have
this the better. Get it down to the seconds from an atomic clock
service, GPS, or the Navy at (http://tycho.usno.navy.mil/cgi-bin/anim).

2) Double check your Lat. and Long in the LX200. Again the more
accurate you have this the better as well.

3) Manually point the LX200 to 0 Hr 90 DEC. Get this as close as
possible using the marks on the Dec axis and RA axis.

4) Go through the polar alignment routine of the LX200.

5) When the LX200 slews to where it thinks Polaris should be, center it
(by moving the wedge adjustments) using a high power reticle eyepiece.

6) When the LX200 slews to it's alignment star, center it using the
keypad and hit enter.

7) Wait about 5 minutes and watch how well it tracks on the alignment
star. This would be a good time to train the Smart Drive. At this point
we are more interested in Dec movement than RA movement, but RA movement
is distracting and should be reduced as much as possible with the Smart
Drive.

8) Do the polar alignment routine again, but instead of moving the scope
to 0 Hr 90 DEC, simply hit "GOTO" on the keypad when prompted to move the
scope to 0 Hr, 90 DEC. This should slew the scope back to Polaris.

9) Recenter Polaris using the wedge adjustments only.

10) When the LX200 slews to it's alignment star, it should be much
closer to center than the first time. Center the alignment star using
the keypad and press enter.

11) Again wait about 5 minutes watching how well it tracks. Repeat 8 -
11 until the scope slews very close to Polaris (within 1 or 2 arc minutes
or about 1/2 an eyepiece field at 250x) and slews equally as close to the
alignment star.

12) Now if you want to refine it further, do a careful drift align.
However, I found last night that simply doing the LX200 alignment routine
as stated above got me so close to perfect polar alignment that I didn't
need to make any adjustments while doing my 10 minute drift alignment.

My pointing accuracy is now as good as it ever was (either in Polar or
AltAz).

I hope this helps.

Chris Vedeler
http://www.isomeida.com/homes/cvedeler/space.htm
Tucson, AZ

Lawrence Harris wrote:

> Could someone suggest a check for this problem?
>
> I have been able to mount my LX200 (1993 vintage) on a proper wedge.
> Trying to align using the manual instructions are proving a problem.
> I have checked the various descriptions of aligning and I am happy
> that I can make them work - but I am not sure whether I am on Polaris.
> The first instructions say drive to 90 dec and 0Hr but you cannot see
> 0Hr displayed. I used star 19 (Polaris) and tweaked the wedge, but I
> wonder if I have actually got Polaris? The reason I am uncertain is
> that although tracking seems quite good, the GOTO is all but useless.
> We are always only just inside the finder. This prevents me using
> control from indoors because I know we will not be near the object.
>
> My conclusion is that I am not on Polaris.
>
> regards
>
> Lawrence
>
> http://www.itchycoo-park.freeserve.co.uk/

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