SSP3 photometer sensitivity
I am seeing an asymmetry in the sensitivity of an SSP3 near the reticle ring. I have been taking readings by placing a star on the ring, itself, at approximately 90 degree spacings. I am seeing a huge difference in counts in the different quadrants, with one sector of the ring showing basically sky counts only, and the opposite sector nearly as many counts as the center of the reticle. This behavior has persisted despite a new reticle alignment by the factory. Has anyone else such asymmetries, and are they indicative of problems in the center of the field, where readings are normally taken?