Astromania Alignment 1.25" Next Generation Laser Collimator 2" Adaptor for Newtonian Telescopes Designed for Reflector telescope, with removable 2" adapter both fit for standard 1.25 inch diameter and 2 inch diameter. Red laser collimation beam with 7 brightness levels, wavelength 635-655 nm; Output power: less than 5mw, much safer for your eyes. This sturdy laser unit allows you to swiftly and precisely collimate your Newtonian telescope. Only when the optics have been accurately collimated can the telescope offer you its full performance. Built with metal material. CR2032 Lithium Cell battery (Not include) ; Accurate collimation in a few minutes provide a more clearer image. The telescope can be collimated by just one person. The precision-made aluminium housing of the laser unit has a front opening from which the laser beam can be emitted. In order to obtain an optimal adjustment, it has a side window allowing a disk oriented at 45 with a central hole to be viewed.This can be then later be used to see whether the laser is reflected back on itself, indicating well collimated optics. This adjustment tool can be used in all 1.25" focusers. We provide you with precise instructions in German and English, with a step-by-step explanation of how to adjust a Newtonian telescope using this laser unit. So, even if you are a newcomer to amateur astronomy, it is very simple to get the optimum performance out of your telescope. The laser comes fully adjusted. It can however be further adjusted if required. It has three openings for adjustment, arranged at 120, which are initially sealed. The battery for the laser can be exchanged at any time; the small screw cap at the rear of the laser must be first unscrewed to allow this.