This is the method I use...
Chuck
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3-D Scope Balance by Dr. P. Clay Sherrod
Message #55967 posting on the Yahoo group LX200GPS
From: "P. Clay Sherrod" <drclay@arksky.org>
Date: Mon Apr 12, 2004 8:46 PM
Subject: Re: [LX200GPS] Re: Suggestions on Max Slew Speed?
This is an issue that has been dealt with before and really SHOULD be in the Files section
permanently (hint, moderators....). To properly balance a fork mounting you must use the
3-dimension Losmandy or equivalent counterweight set and follow the steps below:
1) Aim the telescope due south in the equatorial (polar) mode and tilted about 45 degrees
up from the south horizon; have the 3-D weight screwed as close to the surface of the OTA
as possible;
2) Unlock the declination;
3) Adjust the counterweight in this position by sliding up and down the length of the OTA
until the out of balance situation stops;
4) Turn the telescope straight up (zenith) and carefully unlock...the telescope will want
to tilt either north or south;
5) At this point, the Meade and similar weights are useless because they cannot account for
the perpendicularity of the torque in this position; here is where the 3-D weight system
shines.....the telescope in most cases will want to tilt northward from the zenith...if so,
the solution is simple....unscrew the counterweight AWAY from (perpendicular to) the OTA
until balance is achieved;
6) If the scope attempts to move southward, then the counterweight is too great and you must
go to a smaller size and start over.
NOW....if this does not work, then it is likely because you have heavy equipment on the FRONT
end of the scope that cannot be balanced because of the center of gravity so close to the back
of the OTA....so:
7) Add weight to the rear cell; for most applications other than a very heavy dew shield, the
Peterson rear cell balance is an ideal solution....for others it may not be enough;
8) Thus, use the REAR HANDLE of the OTA to add weights in any way that you can to achieve
front-to-back balance in the south-facing (#1 above) position and repeat the other steps in
sequence once that balance is achieved;
9) Once done, lock the DEC. and unlock it in RA and turn to the SE sky.....if the scope moves
eastward then add some type of temporary weight via a wire tie to the RIGHT fork arm handle;
if to the west, then opposite.
Do it in this order and you will be on your way to perfect balance.
Best of luck!
Dr. Clay
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Arkansas Sky Observatory
Harvard MPC H41 (Petit Jean Mountain)
Harvard MPC H43 (Conway)
Harvard MPC H44 (Cascade Mt.)
http://www.arksky.org/
Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
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