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Aligning the Mirror

February 19, 2019

Mark Wrigley


I’m always getting asked “how do you align the mirror?” on the PiKon telescope. For the best images, it good to get the axis of the parabolic mirror lined up with the axis of the PiKon tube. You can do this in 2 ways:

Mechanical method

One you have built the mirror assembly you can ensure that the spring loaded adjustment bolts are set right by trapping a 5mm (or similar) drill bit between the mirror mount (3D printed part) and mirror base (3D printed art). By positioning the drill bit near each of the springs and adjusting the bolt until it just releases, you will get the mirror reasonably aligned.

Optical method


For little more than £20 (GBP) you can buy a laser collimator. I got mine from Sky’s the Limit. In normal use this would slot into the eye piece of a telescope and bounce a laser beam off the primary (and secondary) mirror. There is a target in the device set at 45 degrees where the laser beam is aimed during adjustment of the mirror.
There is no eye piece in the PiKon, so we have just made a 3D printed alignment tool available. It sits where the spider assembly should go and sets the laser collimator in line with the axis of the PiKon’s tube. It is then a matter of adjusting the spring loaded adjustment bolts until the laser beam, which is reflected off the mirror, hits the centre of the target on the laser collimator.

You can download the .stl file here: Laser Alignment Tool

Screen Shot 2019-02-19 at 10.10.38


One Comment

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  1. September 6, 2022

    Primary (and the only!) Mirror fine collimation with a ‘star test’ should also be possible. Defocus over a bright star and the camera module should be central in the airy disk. Defocus the other way and check again. If it isn’t then adjust the mirror while receiving a video feed.

    Or maybe pop the lens back in and use a concentric circle overlayed on the feed. This would ensure the camera is pointed directly at the mirror and centred.


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