View Single Post
  #1  
Old 15-11-2011, 02:59 PM
swannies1983 (Dan)
Registered User

swannies1983 is offline
 
Join Date: May 2006
Location: Adelaide
Posts: 781
Balance issue or something else?

I have been having major issues guiding in DEC (RA is fine). See here for a few posts made by me http://www.iceinspace.com.au/forum/s...t=53901&page=3)

Basically I get really large corrections in DEC, up to 1-2 pixels from the central line. Potential causes include backlash, balance and stiction. I always tend to guide in either NORTH or SOUTH direction only. However, I have recently chosen SOUTH. The reason can be seen via this video http://www.youtube.com/watch?v=KZk7P1HMLkY I am winding the pulley/belt and you can see that movement is quite jerky when I wind NORTH (towards the ground) but smooth when I wind it up (SOUTH).

Is this simply a balance issue? I have balanced DEC when the scope is horizontal and vertical. However, I tend to slightly balance it eyepiece heavy to engage the gears. When I balance the scope evenly, the jerkiness is evident when winding both up and down.

Maybe backlash? However, there is very little movement in the DEC axis when the clutch is locked.

Just a wild guess, but doesn't PhD calibrate in he NORTH direction? While I assume the jumps won't be as exaggerated during calibration, would "micro jumps" cause a problem in the final calibration? I'm only guessing.....
Reply With Quote