This economical Astro-Tech Laser Collimator permits fast and consistent collimation of a Newtonian reflector's optics, including Dobsonians and astrographs. It works well on telescopes with fast focal ratios of f/5 or lower, where accurate collimation is especially critical for the best images. Its viewing port has a rear-facing bull's-eye target that lets you adjust your telescope's primary mirror while conveniently standing at the rear of the telescope, where the primary mirror adjustment screws are located.
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 Astro-Tech Laser Collimator will make sure that you get the best possible image contrast and resolution every night you go out to observe.
To collimate your secondary mirror, first confirm that your secondary is properly centered under your focuser (either by eye or with an optional sight tube). Adjust the mirror to center it under the focuser if needed, following the procedure in your telescope's instruction manual. Once the secondary is centered, insert the laser into the focuser and observe where the laser beam's red dot lands on your primary mirror when you look at the primary from the front of your optical tube. (If your scope is badly out of collimation, be sure the laser beam is not exiting the front of the scope before looking down the tube.) Most primary mirrors will have a factory-installed center spot or glued-on center donut to help you locate the center of the primary mirror. Simply adjust the secondary mirror's collimation screws as needed until the laser's red dot lands on the center spot or the hole in the middle of the primary's center donut and your secondary will be properly aligned with your primary.
Next, move to the rear of the telescope, where the primary mirror is located, and observe where the laser beam's red spot falls on the white bull's-eye in the viewing port of the collimator. Adjust your primary mirror's collimation screws until the red dot lands on the laser-emitting hole in the center of the collimator viewing port and you are done. Your scope optics are collimated.
For extremely critical observing or imaging with a very fast focal ratio reflector, you might want to follow up with a star test for any final collimation tweaking that might be needed. For 99% of of your observing and imaging, however, the simple and quick laser collimation described above will be more than satisfactory.
The Astro-Tech Laser Collimator's all-aluminum body measures only 4" long, so it can easily fit into your accessory case or pocket for trips to the backyard or distant dark sky sites. It can be used with any 1.25" telescope focuser, but also comes with a 2" adapter at no extra cost so you can use it in any 2" telescope focuser.
The Astro-Tech Collimator weighs only 2.4 ounces (4.8 ounces with the 2" focuser adapter). It has a combination rotary on/off switch and brightness control with seven brightness levels. The rotary switch is stiff in operation to avoid accidentally turning on when being stored away. It is powered by one 3V CR2032 lithium battery located in a battery compartment on top of the rotary switch. The supplied battery is good for many hours of use and replacement batteries are readily available from any store that sells camera or watch batteries. When replacing the battery, be sure to install the new battery with the positive (+) marking facing you.
The <1mW laser diode has been factory-aligned in the collimator's body, resulting in consistently pinpoint collimation. With laser collimation quick and easy, you can keep your reflector telescope serving up the sharpest, clearest views possible, night after night, year after year.
Warning: The Astro-Tech Laser Collimator complies with US 21 CFR 1040.10 and 1040.11 and is FDA Certified and IEC compliant. It is a Class II laser product, and you should avoid direct eye exposure. It is not designed to be used as a toy or laser pointer.
Please note that this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.