Starlight Instruments Single Red Beam 2"/1.25" Laser Collimator - 635nm
- Single red beam operates at 635nm for twilight use.
- The Howie Glatter Laser Collimator incorporates a solid state laser diode that does not fade or change with time and use.
- Factory-aligned to 15 arc-seconds providing 0.1 inch accuracy at a distance of 20 feet,
- The Howie Glatter 2"/1.25" Laser Collimator is shock resistant to keep its alignment - even when dropped.
- Includes 123A lithium battery, 1mm aperture stop, removable diffractive element, case, collimation rings and instructions.
When I started manufacturing laser collimators I realized that in order
to produce consistent and accurate results they must be highly resistant
to mechanical shock, so that internal laser alignment is maintained. I
experimented with this aspect of collimator construction and developed a
design which tremendously increased shock resistance. After aligning
the laser within 15 arc seconds, I shock test each collimator by
whacking it against a block of urethane plastic (urethane prevents
marring), striking it at least a dozen times on three axis. I then
recheck the laser alignment, and if it has not changed the collimator
passes. I believe this is the most important difference setting my
collimator apart from all others I know of. They will withstand a shock
equivalent to dropping from eyepiece position, up the ladder on a big
Dob, without alteration of laser alignment.
The beam from all red diode lasers used in collimators is fuzzy-edged
and elliptical in cross-section. When collimating, you sometimes must
judge the location of the center of the spot by eye. To improve
collimating precision, all of my collimators (except 532nm) are supplied
with a removable accessory plastic aperture stop having a 1mm hole,
which push-fits into the laser aperture. It produces a tiny, circular
beam impact which allows more accurate alignment. With the holographic
collimators, it is not used at the same time as the holographic feature,
and the diffractor must be removed to install the stop. With the stop
inserted the beam impact at a distance of one meter or more looks like a
star diffraction pattern, with a central dot surrounded by diffraction
rings. The surrounding rings can help in centering the beam very
accurately.
I offer the red holographic collimators with a choice of either 650
nanometer or 635nm wavelength. The two lasers have the same radiometric
power output, but because the human eye's sensitivity to the shorter
wavelength is greater, the 635nm. laser appears about two or three times
brighter. The higher cost of 635nm laser diodes increases the
collimator price, but it enables holographic collimation in brighter
ambient light. If you intend to collimate in early twilight, it is a
good choice. In darkness, however, the 650nm laser is quite adequate.
Because single beam collimators concentrate all the laser light in the
central beam, the 650nm laser is quite adequate for them."
Precise... Accurate... and Durable... What more could you ask?
