Is binocular collimation difficult?
Getting good collimation in each half of a binocular telescope is not much more complicated than monocular collimation. The same kind of controls are required for the primary, secondary and focuser. Because the optical train of a Newtonian binocular adds a tertiary mirror, it also must be adjustable. A laser collimator helps. Fortunately, the tertiary is similar to a 45 or 90 star diagonal: it is close to the focal plane and has a less harmful effect on collimation than other errors. Collimation procedures for the individual telescopes of a binocular are no different than those used for monocular telescopes. My 12″ binocular has a Barlow lens, which must be temporarily removed before collimation can be performed with a laser or Cheshire collimator.
