This 2” single beam laser collimator makes it easy to collimate any type of telescope that has a 2” focuser. Optics that are out of collimation (with optical elements that are not all exactly aligned on the same optical axis) cannot produce good images. Stars will be elongated or lopsided, planetary details will be hazy and low in contrast, and binary stars will be difficult to split cleanly. Regular collimation with this highly accurate laser collimator will make sure that you get the best possible image contrast and resolution every night you go out to observe.
Precisely centered inside this 2” Howie Glatter Laser Collimator’s machined aluminum body is a solid-state 5 milliwatt laser diode. This emits an intense beam of red laser light exactly along the central axis of the cylindrical collimator body. The laser beam acts as a “reference line” to guide you in adjusting the alignment of your optics to optimize your scope’s collimation. The laser emits monochromatic red light at a wavelength of 650 nanometers. A rotary switch in the end of the body turns the laser on and off.
In use, the collimator is placed in the telescope eyepiece holder and turned on. Its laser beam travels through the scope, reflects off the scope’s optics, and returns to fall back on the flat end of the collimator. If the returning laser beam falls exactly on the small black aperture that is emitting the beam, the scope is in collimation. If the returning beam falls on the collimator’s 2” diameter matte white face surrounding the emitting aperture, the scope is out of collimation. Out-of-collimation optics are simply adjusted until the returning beam lands squarely on the aperture emitting the beam.
CAUTION: The Class IIIa laser in this collimator has a maximum output of 5 thousandths of a Watt (5 mw). This is quite safe if it is used with reasonable precautions. However, direct or mirror-reflected eye exposure should be avoided! Detectable eye damage can occur if the laser beam is focused on the same area of the retina for as little as 0.25 second. Therefore, take care when collimating your scope to be sure that the beam does not enter anyone’s eye directly, including your own. Keep it locked away when not in use and out of the hands of children. It is not a Star Wars light saber for them to play with.
There is no danger in viewing the beam’s impact on a surface that produces a diffuse reflection, such as the face of the laser collimator itself. The beam impact may also be safely viewed on a mirror or lens surface, if the reflected or transmitted beam is not directed towards your eye. A Newtonian or Cassegrain that is badly out of collimation may allow the beam to exit the front of the telescope, so when collimating these scopes, check first by pointing the telescope at a wall or screen to see if the beam is getting past the secondary or diagonal mirror. With a refractor, the beam will always exit the front of the telescope, so run a strip of masking tape across the diameter of the dew cap opening as a safety beam stop.
Two important considerations in choosing a laser collimator are the accuracy and stability of the laser beam alignment to the cylindrical axis of the collimator body. This collimator’s alignment tolerance is an impressive fifteen arc seconds. In order to ensure that this level of accuracy is always available, the collimator is designed – and tested – to withstand a shock equivalent to dropping the collimator from the eyepiece position on a tall Dobsonian telescope, without altering the fifteen arc second alignment. Most other laser collimators cannot withstand this kind of accident without loss of alignment.
The collimator comes with a single CR123A lithium battery that will power the laser for approximately 40 hours. Lithium batteries maintain a stable output voltage for their entire lifetime, giving maximum laser output. Replacement batteries are widely available (they are commonly used in point-and-shoot cameras) and usually sell for about $6-$7. The collimator is supplied with one battery, a plastic storage case, press-on collimation “donuts” for use with Newtonian reflectors, and very complete instructions for collimating telescopes of all optical types.