RE: ATM Alt Balance and Eyepieces

[Doug Tanaka <dtanaka@seanet.com>]

Thanks, all, for your responses!  I have heard of replacement weights to make up for the 
lost weight of a heavy eyepiece, but it seems to me this applies more to telescopes with 
a fixed balance.  My problem is not balance, per se, because I can quickly and easily 
adjust the balance using a bungee cord system.  I guess it's less a problem of static 
balance as much as dynamic balance.  I'm thinking the problem is that I don't have enough 
friction on the trunnions.  I can fine tune the balance so the upper end is just shy of 
being too heavy, but when I remove the 31mm Nagler it always drifts up.  I don't know how 
I'd be able to switch the eyepiece with a replacement weight (sand, bb's, brass ring, 
etc.) quickly and smoothly enough for the tube not to drift a bit during the switch.  It 
brings to mind Indiana Jones swapping the bag of sand for the gold head.  Larger 
trunnions would probably work, but my wife's concession to this hobby was that the 
telescope had to fit underneath the bed in our van - 10 3/4".  The trunnions pivot down 
flush with the top of the mirror box for storage and to still fit under the bed, are 
maxed out at 16".  Not to mention it would mean redoing my rocker box.

So far, it looks like the traditional approach would be to move the Teflon pads further 
apart since this would indeed increase the friction.  What I don't know, and what I would 
like some feedback on, is whether or not the increase in friction would be enough to 
effect ease of movement - enough, that is, to make me regret having done so.  The Teflon 
pads are currently spaced at 70 degrees.

A more radical approach would be to try Nil's string/stick method.  I'd just have to be 
sure my eyepiece case is within stretching distance!  Otherwise, I'll try hooking up a 
small, reversing DC motor with rack and pinions to move two tensioning rods in and out 
(my solenoid works well, but the heat problem is pretty severe).  With the switch near 
the eyepiece, I can lock things in place while looking through the eyepiece.  It would 
have the added advantage of being able to lock the OT in place when it wasn't in use. 

Thanks for all your help,

Doug Tanaka