View Single Post
  #12  
Old 05-02-2015, 06:51 PM
wasyoungonce's Avatar
wasyoungonce (Brendan)
Certified Village Idiot

wasyoungonce is offline
 
Join Date: Jul 2006
Location: Mexico city (Melb), Australia
Posts: 2,357
Quote:
Originally Posted by John K View Post
The drive actually uses a friction clutch that is tightened to drive the steel roller which rives the horseshoe ring. So no belts involved in the RA drive.
Thanks I was unsure from the pics.

Quote:
Originally Posted by John K View Post
I actually sent the drive back to Losmandy soon after I got the scope because the crystal they had installed caused a rocking back and forth motion to the RA drive.
Quite odd...me thinks this would be a stepper drive IC issue. Anyway.

Quote:
Originally Posted by John K View Post
I actually now think that JMI have not been able to get the steel roller to be 100% accurate in size to allow the RA drive to operate accurately at such a high focal length.

So another solution would be to have a slightly smaller RA roller that turns the RA horseshoe ring slightly slower - BUT, that might cause it to go too slow as well.
looks as if they have it pretty right though.

Quote:
Originally Posted by John K View Post
Last night I did image at a different rate setting and added some weight on the East side of the scope and this has definitely made a difference and eliminated 50% of the issue. As the scope is not permanently mounted and is wheeled in and out to a pre dedicated pad, this also contributes.
Excellent. This sounds as if your on the right track
Reply With Quote