Rotator balance

Especially in the case that asymmetric instruments are mounted on the adapter there is a risk of damage to the rotator drive if the telescope power is lost while pointing away from zenith. Of our core instruments (and the one that is also mounted most often) ALFOSC is the most asymmetric and the precise amount and position of the weight needed to balance the rotator when ALFOSC is mounted was defined. A specific flexure was made and is now part of the standard installation of ALFOSC at the telescope.