Re: ATM more drive dreaming

[Andy Saulietis <iss@pvtnetworks.net>]

Ron writes,

>    When you get right down to it a drive need do only one thing. Provide
>a constant rate of motion without any jerkiness,drift, or other unwanted
>motion. That's it. 23hr. 53min and some debatable change. If you had a
>sprocket and chain system that always had a weight it was pulling against
>eliminating any backlash, you would be set. No matter how long an exposure
>you made, as long as you had enough chain, who cares? A stepper motor
>could pull the chain draped on the sprocket (polar axis). The end of the
chain
>would have enough weight dangling from it for tension. I'm sure it ain't that
>simple, but hey we can dream right?

I've been using roller chain/sprocket drives on large
alt az scopes for several years. They're great for visual
use but not quite good enough for CCE/photo imaging
because of periodic error and small amplitude random
tracking errors; they're designerd to transmit power and
are not designed for accuracy & linearity.  



Andy Saulietis
ISS Enterprises
39 Silver Fox Trail
Mayhill NM 88339
505-687-3067 voice
505-687-3021 fax, call voice or e-mail to set up
e-mail: iss@pvtnetworks.net