This can be done by simple visual methods such as looking down the optical assembly with no eyepiece to make sure the components are lined up , by using a Cheshire eyepiece , or with the assistance of a simple laser collimator or autocollimator .
It is done by simple visual methods such as looking down the optical assembly with no eyepiece to make sure the components are lined up , or with the assistance of a simple laser collimator or autocollimator .