I just got back from the observatory and have some performance
data for the Dec drive mods on my 12" LX-200:

With a backlash setting of 00, my Dec drive takes 2.5 seconds to
change direction, at 30, it takes 1.5 seconds and at 55, 0.5 seconds.
The larger setting, 55, was just starting to make the star jump when
changing directions. This is on a 12" LX-200 with 27 lbs. of
accessories.

I also tested the assembly with 14 lbs. of simulated accessory scope
weight, 7 lbs. of Losmandy plate assemblies and 19 lbs. of counterweight
which resulted in only 25 mA more power needed when slewing in RA
or Dec without the added accessories. Prior to the Dec mods, I could
not use so much weight (42 lbs with heaters) with so little current gain.

Weather wasn't cooperating, however, I did manage a brief check of
pointing accuracy. Since this scope is on a permanent mount, I just
pointed the scope at a star at a significant declination and RA away
from the pole star, which I synced on. I then inserted a CCD camera
and put the LX-200 in the HP mode and went to M-42. The sync star
was almost near the center of the CCD chip. I centered it slightly
and took a 6 second image of M-42. Then, I entered M-31 which was
in a part of the sky quite far from M-42. This time, the sync star
was dead center on the CCD chip.

Other than a very loose Dec axis which could potentially damage
the scope and accessories if one were to release the Dec drive
that was not balanced, I am very pleased with the results. The Dec
mods have eliminated stiction, increased Dec drive response
significantly, improved pointing accuracy slightly and do what I
really wanted, allow at least 42 lbs. of accessories to be used
without RA or Dec drive strain.



--
Michael Hart
Husen Observatory

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