Alstar Red Laser Collimator for Newtonian Telescopes 1.25 inch 7 Brightness Levels Review (2026)

Who needs a laser collimator like this

Anyone who owns a Newtonian or Dobsonian reflector telescope knows that mirror alignment, called collimation, drifts over time from transport, temperature changes and normal handling, and it directly affects how sharp the views look at the eyepiece. This laser collimator is built for reflector owners who want a fast way to check and correct that alignment before a session rather than relying only on a star test in the dark. It suits both new Dobsonian owners learning collimation for the first time and experienced users who want a quicker routine check than a Cheshire eyepiece alone provides, especially useful right before a planetary observing session when sharp focus matters most.

How the design and brightness levels work

The collimator fits the standard 1.25 inch focuser size found on most Newtonian telescopes and includes a removable 2 inch adapter, so it also works in larger focusers without needing a second tool. It projects a red laser beam in the 635 to 655 nanometer range at under 5 milliwatts of output, and offers 7 brightness levels to suit both a well-lit room for practice and a fully dark observing site where a dimmer beam is easier to read. A side window with a 45 degree disk lets the user check whether the laser reflects back on itself, which confirms proper alignment, and three adjustment screws set 120 degrees apart allow for recalibrating the unit itself if it ever drifts.

Using it and keeping it working

In practice, the collimator inserts into the focuser like an eyepiece, and the beam projects down onto the primary mirror and back up to a target on the collimator's face, guiding adjustments to the secondary and primary mirror screws until the beam lines up. It runs on a single CR2032 lithium coin cell battery, which is not included, so it is worth picking one up before the first session. Because it is a budget-priced laser tool from a lesser-known brand rather than a premium name, it is good practice to verify the laser itself is properly self-aligned against a Cheshire eyepiece or autocollimator when it first arrives, since a misaligned laser will give a false collimation reading.

How it compares with other collimation tools

Against other options in the same collimator comparison, this Alstar model ranks near the bottom of the group, behind the HoTech SCA-2C and the similarly specced SVBONY and Astromania laser collimators that also offer 7 brightness levels in a 1.25 inch body. Those alternatives are built to the same basic laser design but come from brands with a longer track record for factory self-alignment accuracy. The Celestron 94182 Cheshire eyepiece and the Astromania Cheshire without a laser, both further up the same list, use an entirely different non-laser method that some experienced users trust more since it has no battery or internal laser diode that can drift out of calibration.

Verdict and who should choose differently

This collimator earns our score of 7.6 out of 10 as a functional, budget-friendly way to speed up collimation checks on a Newtonian telescope, with a useful range of brightness levels and the flexibility of the included 2 inch adapter. It suits anyone who wants a quick laser-based routine tool and is willing to verify its factory alignment before trusting it fully. Buyers who want the most dependable long-term accuracy without worrying about laser drift or batteries should consider a Cheshire eyepiece instead, and anyone collimating a telescope with a 2 inch focuser as the primary size should double check the adapter fits their specific focuser drawtube.

Frequently asked questions