This accessory allows you to simply and accurately adjust the optics of your Newtonian telescope. Just insert the laser collimator into the telescope's focuser and you can see if the mirrors are collimated correctly or not.
The advantage of using a laser for collimating - rather than an eyepiece or the just by eye - is that it is simply more accurate. You can collimate the telescope using the laser, outside after arriving at a dark sky site, in seconds and always have two hands free.
As the laser is 360° rotatable you can, for example, when adjusting the primary mirror, rotate the laser towards you and see directly how the laser spot moves on the disk. You do not then have to constantly go to the focuser to see what effect the last adjustment has made or how the mirror has moved.
