Explaination for Dec movement hysteresis?

[peteri]

Hi,

I have an old 2120 LX6 permanently mounted in my roll-off observatory. I have noticed that the movement on the declination axis has some hysteresis - i.e. it does not follow the vertical line of an eyepiece reticule, but instead follows an arc to one side, and then to the other side when I move the declination axis using either the manual knob or the dec motor. Does this indicate loose or worn bearing surfaces?

[Kaptain Klevtsov]

Could it just be that the reticle isn't properly aligned? Other than that I can't think why it would do that. I'd not worry about it anyway as once you've aquired your target you dont need to move the Dec. axis anyway.

Kaptain Klevtsov

[peteri]

Thanks for your response Kaptain Klevtsov.

However, I don't think it's the reticule being misaligned, since the star traces an arc either side of the vertical line (sort of like (|) if you see what I mean), whereas the RA movement is spot on parallel to the horizontal line of the reticule. This hysteresis will be a problem when auto-guiding on a star - any correction made by the guiding system to compensate for drift on the declination axis will result in an unwanted displacement on the RA axis, which will then lead to an unnecessary RA correction and possible hunting around the "target" position of the star.