The coherent collimated beam of light generated by lasers has made them a natural for collimating optics and
they have been used for that purpose since the 1960's. The introduction of lightweight, low-power consumption
laser diodes has now made them readily available to amateur astronomers. The popularity of using a laser for
collimating optics stems from two advantages over other popular collimating methods. Collimating with a laser
is fast and easy. There is also less need for interpretation as collimation proceeds and the laser is equally
convenient to use at night. These advantages have made the laser collimator the first choice for experienced
and beginning amateur astronomers.
Astrosystems developed the first commercially available laser collimator in 1994 with the AstroBeam I, a
1.25"/2" model that was an instant success. The first lasers made collimation far more intuitive and easy for
beginners to learn.
The first two steps, preparation and mechanical alignment, need only be performed the first time the telescope
is assembled. Thereafter, only the optical alignment and star testing are needed to collimate your telescope.
Don't underestimate the importance of mechanical alignment. Most troublesome collimating jobs can be traced
back to mistakes or assumptions regarding the placement of components.
Indispensable for fast and convenient collimation of Newtonians! You will wonder how you ever lived without one. Our collimator uses a 650nm, 4.5mW, class IIIA red diode laser that is very easy to see and safe. Collimate either day or night! The body accurately fits into the focuser and can be adjusted for an accurate fit using the nylon set screws. You'll be able to collimate your telescope mechanically and optically. Also allows you to diagnose loose or misaligned parts. The body is CNC machined from solid aircraft aluminum, then black anodized. The handy Barlow lens is magnetically attached to the laser. The Barlowed laser achieves the accuracy of a Cheshire collimator with the ease and simplicity of a laser collimator in three easy steps.
Step 1. Mechanically position the optical components and supports (need only be done once) using a sight tube (home made is fine)
Step 2. Optical Collimation
Adjust tilt of secondary mirror
Using the laser (without Barlow Lens) and the collimation screws supplied on the secondary holder, adjust the
secondary mirror tilt to center the laser beam from the secondary in the primary mirror center spot. This can be
easily seen from the front end of the telescope. With truss tube telescopes, get close to the primary and adjust
the beam in the center of the spot, extra accuracy at this step will improve the final results.
CAUTION: If the tilt of the secondary is off when starting, the return laser beam from the primary mirror may
miss the secondary completely and exit the front of the tube. DO NOT look into the laser exiting the front of
the tube or allow anyone else to do so. Incidental exposure to a 3-5 milliwatt laser is not immediately harmful
but we recommend you avoid any unnecessary eye exposure.
Step 3. Adjust the tilt of primary mirror with the Barlowed Laser
Snap the magnetic Barlow lens on the front of the laser and insert in the
focuser. The diverging beam will cover the primary mirror's center spot,
but will not necessarily look concentric or round (not a problem). The
primary collimation screws are used to adjust the tilt of the primary so the
silhouette/shadow of the primary center spot is centered on the hole on the white screen on the bottom of the laser. The matte
white surface makes it easy to see the image and center it accurately.
Telescopes with an open bottom end can be adjusted from the primary end
by looking past the primary to the reflection of the bottom of the laser as
seen in the secondary mirror. It is then a simple matter to adjust the
primary mirror so the center spot image is centered on the bottom of the laser body. Telescopes with a closed
cell can be adjusted incrementally by moving to the front of the tube to observe the reflection of the bottom of
the focuser and laser body as seen reflected in the primary mirror. Having someone help at this stage speeds the
process. Once the return image is centered on the hole in the laser body, the telescope is collimated. [Note: you have to be somewhat far-sighted to do this from below]
Axial beam lasers are subject to minor centering errors resulting from the return beam from the primary mirror that can be difficult to detect. These minor errors can make a substantial difference in achieving accurate collimation on shorter (f/6 or less) telescopes. When using a Barlowed laser, it is possible to achieve 20 thousandths of an inch centering or better on the return beam. This is usually precise enough collimation for general observing, but an autocollimator can reduce the residual errors to vanishingly low levels, resulting in the sharpest-possible images. An instruction booklet is included as well as the 2 AA batteries.
Care / Maintenance / Changing batteries
DO:
Keep your laser collimator clean and avoid rough handling.
Use a lens duster or canned air to blow any debris off the laser module lens.
Replace aged batteries, even though they may still function.
The Laser Collimator uses 2 AA batteries. The laser is rated for 5 volts maximum, operating at higher voltages
will void the warranty and shorten the laser diode life. If batteries are older than 2 years but still functioning,
replace them anyway. Old batteries have a higher probability of leaking if accidentally discharged.
Use care when removing battery pack and changing batteries.
On a table at a comfortable height, remove the thumbscrew that holds the cap. Slide the battery pack out of the
body, taking care not to pull the wires attached to the laser module. Also be sure not to let the battery pack or
cap hang free, placing undue strain on the laser module wires. Use a small Phillips drive screwdriver and
remove the screw in the battery pack. Slide the cover off and replace the batteries. Replace the battery pack
cover and gently tighten the screw. Place the foam cushion next to the battery pack and reinsert into the laser
body. Replace the cap and secure with the thumbscrew.
DON'T:
Attempt to adjust the collimating screws on the laser body.
If you feel the diode module is not producing a beam parallel with the laser body, simply return the laser to
AstroSystems with return postage for free factory service.
Do not expose the laser to temperature extremes, especially heat. No dashboards or car windows.
Do not run the laser for extended periods of time (over 30 minutes).
This can overheat the module. Allow to cool if it will be used for an extended time.
Laser Safety
The Laser Collimator will produce up to a 4.5mW beam in the deep red (650nm). Although this is the same
power and type produced by laser pointers and grocery scanners, it is advisable to avoid any accidental eye
exposure. This type of laser diode has a fast divergence (spreads out) and is well below the safety threshold of
1mW after traversing 80 feet or more.
Never allow children to operate or play with the laser and keep the laser in a safe place where it cannot be
misused by curious family or friends.
Use the laser only for optical collimation of telescopes. Make sure the front of the telescope is covered during
the first stages of coarse collimation. If the secondary mirror or primary mirror is misaligned the return beam
may miss the secondary mirror and exit the front of the tube. Passing your hand in front of the telescope
quickly shows if the beam is exiting the front of the telescope. If this is the case just use your hand as a block
while adjusting the secondary until the secondary mirror intercepts the beam. We cannot control the use of this laser product. All responsibility for its proper use is assumed by the purchaser.
Laser Characteristics
The laser module used in the Laser Collimator is fully integrated. The module contains the diode laser, power
supply, heat sink and collimating lens. The laser is optimized for the smallest spot size at 20 feet (6m).
At
short or long distances the spot may be slightly elongated. It is a simple matter to interpolate the position of the
center of the spot when aligning at extremely short or long distances.
The laser spot size is affected by
temperature. As the temperature falls below about 50 degrees F the spot size will slowly grow. This will affect
telescopes with a focal length over approximately 100 inches. This situation can be remedied by using the laser
immediately upon set-up before it has a chance to become cold. It can also be kept in a warm place until
needed, such as an inner pocket or warm car.
A real bargain! 
