Re: ATM Adjustable virtual counte weight

[John Swenson <johnswenson1@attbi.com>]

Jim (and the others who replied), I was thinking of using a virtual
counterweight ( a la Tom Krajci) made of springs and strings (I have a
LOT of 450 Plus left over from the string scope experiments!)

One of the problems with the traditional real counter weight system in
this case is that the weight will be no where near the scope axis, thus
as it goes from horizontal to vertical the effect is significantly
different than if it were on axis. I tried this out with a real weight
and the effect is noticeable. To get away from this effect the weight
has to fairly far away from the pivot (ie small weight on long arm), I'm
trying to get away from "long arms" with this design. Of course there
are ways to mount the weights that get around this problem, but thats
not how I did it when I was experimenting <g>. The virtual counterweight
came to mind as a way to get around this problem.

The virtual counterweight system seems perfect for this purpose, if
properly layed out it exactly counteracts the extra weight over the
whole range of motion. Unfortunately I don't know how to make this
system adjustable.

I've never heard of the virtual system being used on a dob-fractor but I
don't see why it wouldn't work. I've looked over the archives and on the
net and have not heard of anybody doing an adjustable virtual
counterwieght system on dob or otherwise.

John S.