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Subject: Re: [M]: LX200 parking
From: Bill Arnett
Reply To: mapug@shore.net
Date: Sat Apr 11 00:57:43 1998
At 1:54 PM -0700 4/10/98, Paul Goelz wrote:
>...
>To park the scope so it is aligned the next time it is used, try this
>(assuming of course that it is currently aligned and tracking OK):
>
>1. Place the scope in LAND mode. At this point, timing becomes
>non-critical, as the scope will continue to update it's view of the sky
>even though it is not moving the OTA.
>2. Slew to zero degrees ALT and AZ (easy way is to press MODE till you get
>to the RA and DEC display, press ENTER to go to the ALT AZ readout, then
>press GOTO. The display becomes all zeros. Press ENTER twice, and it
>slews to zero degrees ALT and AZ.)
>3. At this point, you can either leave the scope powered up or shut it
>down. Either way, it will be aligned the next time you put it back into
>ALT-AZ mode, no matter how much time has elapsed....... well, I assume it
>doesn't matter. I have tried it for about a half hour, but I would assume
>unless there is a quirk at the change of day, it should work no matter
>what, up to the limits of the internal sidereal clock...
My guess is that the above procedure will work but for a different reason.
My theory is that is does NOT "continue to update it's view of the sky" in
LAND mode rather it simply assumes that it is pointing south and level when
first entering ALTAZ mode (either at power up or when going from LAND to
ALTAZ). This is the so-called "zero star alignment". If your
lat/long/time are correct and your tripod is level that is sufficient to
establish alignment.
One could distinguish between my theory and Paul's by pointing at some
other point than due south and level and trying Paul's procedure. If it is
indeed "continueing to update it's view of the sky" then the procedure will
work; if my theory is correct it will be off by the distance between the
chosen point and the assumed south/level point.
---
Bill Arnett "Science is a way of trying
San Jose, CA USA not to fool yourself." -- Feynman
billa@zNet.com <URL:http://www.seds.org/billa/>