1.25" Cheshire Collimation Eyepiece for Refracting Refractor Telescope Short

has a 45 degree plate for easier visual accuracy.Collimation is the alignment of elements inside an optical system like a telescope. It can take some time getting used to aligning both the secondary and primary mirrors and this. Short collimator can make it much easier.The short collimator for mirror (reflector) telescopes. Colimating a telescope consists of adjusting the tilt and position of the mirrors and lenses to ensure that the focal point reaches optimum focus at the point from which the image will be viewed (the eyepiece or possibly a camera). To get the most out of your scope for Newtonian you really need to align or collimate the mirrors.