[Dekker (Derrick)]

Hi Nick,


I have the same scope which is also afflicted by the same problem where the tension changes when you change altitude. It may be partially self-inflicted; I think I messed up the order of the washers / spacers at some point in the past after taking the optical tube off the mount and then re-assembling.


I was able to improve the situation (but not completely resolve) by re-ordering the washers and plastic spacer. I will take some photos when I'm home and get the scope out of the cupboard.

Edit: Added pictures.
Other (better) Dobsonians do not have this problem. I replaced my FirstScope with a Skywatcher Heritage 150, and it has a roller bearing between the tension adjuster knob and mount that prevents this issue.