Howie Glatter Single 650nm Red Beam Laser Collimator - 1.25"/2"

The key difference is its verified alignment and durability. Each Howie Glatter collimator is aligned to 15 arc-seconds and then subjected to a rigorous shock-testing procedure, struck at least a dozen times on three axes, to ensure it maintains that alignment even after being dropped or mishandled.

The 1 mm aperture stop simply push-fits into the laser opening. It sharpens the fuzzy, elliptical beam from the raw diode into a tiny, circular point. This produces a star-like diffraction pattern on your primary mirror, allowing for much more precise centering of the beam on your center mark.

Howie's instructions: the return spot on the collimator face can be seen from the front of the telescope, looking down the tube, by double reflection in the primary and secondary, and you may need a helper to turn the primary screws while you watch. The primary can also be adjusted by making the up-going and down-going beam impact points on the secondary coincide; with an open tube this can make solo collimation easier.

Yes. When placed in the focuser (without a diagonal), the Howie Glatter laser projects a beam through the objective lens. You can check that the focuser drawtube is aligned with the center of the objective. The reflection from the objective lens surfaces back to the collimator face is then used to adjust the objective cell's tilt. For safety, always place a beam stop, like a piece of masking tape, across the dew shield opening to prevent the beam from exiting the front of the telescope.

The front of the collimator has a 3/8-32 thread. This allows you to attach optional accessories sold separately, such as Howie Glatter's holographic attachments (square grid, concentric circles, etc.) or a Barlow attachment for more advanced collimation techniques.