ATM Dob mount motion

["Chris Cook" <turfa@hutch.com.au>]

I have recently completed the mount for my 8" dob and have been
experimenting with methods of improving the motion. The mount basically
follows the 8" design shown in Kriege & Berry's book "The Dobsonian
Telescope" (an excellent book BTW) with large diameter altitude bearings.
The bearing surfaces are an Australian equivalent of the Ebony Star textured
laminate and Magic Slider teflon pads.

I had followed advice from the list about using silicone car wax on the
bearing surfaces and found that this gave me quite good motion. Spraying
Armour-all (automotive vinyl protectant) on the bearing improved the motion
further with only very, very slight "stiction" present.

When moving my girlfriends motorised treadmill  I found a small spray can of
teflon lubricant that was supplied to lubricate the underside of the
rubberised running surface. I tried this on my bearings and found that the
resulting motion was superb. Both alt & az  motions are super smooth with
not a hint of stiction & I can move the mount in both axes simultaneously at
extremely slow rates without sticking.

I'm not sure how much this stuff costs, but will soon find out as I used up
the last of the can (sure to get in trouble over that !). The brand of the
treadmill is Tunturi (made in Finland I think) & I expect that the teflon
spray should be available from most good exercise equipment suppliers.

Give it a try !!!!!!!


Chris