ITEM NAME:1.25" Cheshire Collimating Eyepiece New for Newtonian Refractor Telescopes Metal -Fits in 1.25" focusers and easy to  	use;simply cap the telescope, remove the diagonal, and place the eyepiece  	directly in the focuser. -For aligning optics of Newtonian reflectors, Dobsonian reflectors, and  	Schmidt-Cassegrain Telescopes (SCTs). -The short collimator for mirror (reflector) telescopes has a 45 degree  	plate for easier visual accuracy. -Item was made by aluminum with crosshair at the bottom allow quick and  	precise centering of the optics. -This collimation eyepiece can be used for precisely collimating the  	Newtonian and Schmidt-Cassegrain reflector telescopes for better image  	quality. To get the most out of your Newtonian scope you really need to align or  	collimate the mirrors. 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 has a 45  	degree plate for easier visual accuracy. Collimation is the alignment of  	elements inside an optical system like a telescope. 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). Specifications: Material: Aluminum Metal Structure Size: 32mm * 65mm / 1.25in * 2.56inch 1 * Collimating Eyepiece.1   Collimating Eyepiece. To get the most out of your Newtonian scope you really need to align or collimate the mirrors. -Item was made by aluminum with crosshair at the bottom allow quick and precise centering of the optics.