A Newtonian telescope has 2 mirrors which occasionally go out of alignment. Alligning the mirrors of a telescope is called “Collumation”. A ‘laser collumator’ eyepiece helps with the alignment. After inserting the collumator into the eyepiece holder and turning on the laser, we aligned the secondary mirror to the primary mirror using small hex wrench on the 3 adjustment screws to move the red dot into the center of the primary mirror. Next we aligned the primary mirror by turning the adjustment thumb screws on the back of the optical tube assembly (OTA) – and sighting the returned laser dot on the target at the side of the collumation device.