Joe,

Our 16-incher had originally somewhat similar pointing problems that were
located to wrong encoders. There was about 3 percentage relative error on
all slews. After the motor assemblies were replaced we have had good
pointing. We are doing the one-star alignment every night, our scope is on
equatorial mount.

I quess (even if I dont remember trying it then) that the two-star alignment
takes account of the encoder errors, it just measures how many pulses there
are for a known sky distance and adjusts the scale by that. Our scope was
manufactured early 1999; maybe yours from the same time and maybe Meade have
installed the wrong encoders to several scopes.

Btw, it is easy to test the encoders by making a 360 degree slew and
checking the coordinates on display.

Hope this helps,

arto

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-----Original Message-----
Sent: 9. elokuuta 2000 18:30
Subject: ÄMÅ: 16" LX200 - does yours hold alignment?


The staff at Frosty Drew Observatory, tired of weeks of cloudy Friday
nights, had our own private observing session last night (our only
perk, but a good one!). Without the crowd queueing up well before
sunset, I had the opportunity to do a leisurely two-star alignment
with our 9mm reticle eyepiece, and had excellent accuracy on all the
GOTOs, even across a wide arc of the sky.

This raised a question to me, answerable only by other folks who are
charged with the care and feeding of these magnificent beasts.

I've done 2-star alignments before, and have good results. This
accuracy never seems to survive a shutdown, even though we religiously
follow the parking sequence given in the manual. I've tried setting
the time to within 1 second of an atomic clock each time I start the
scope, but that hasn't helped. We've tried SYNCing on objects as we
observe; we've tried not SYNCing. No matter what happens, we find that
if we didn't do an alignment that evening, we can be off by as much as
30 arcminutes on a relatively short slew.

So - if you have a permanently mounted 16", how well does yours hold the
alignment? Am I just asking too much of this procedure? Our scope is
mounted alt-az, if it makes a difference.
--
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Without deviation from the norm, "progress" is not possible. - FZappa

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