How to collimate your telescope in 90 seconds

Mis à jour : 28 oct. 2019

Collimating a telescope is pretty easy, especially if using a laser, but first timers might get confused by this simple process and end up breaking one of their mirrors (yes, we did).

We decided to make this tutorial, as well as a video (which you can find at the end of this post). As for most of our tutorials, this will be quick and straight to the point!

If you just bought a laser collimator, please make sure it is collimated! You can do that by placing it on a table not too far from a bright wall, and turning it on. Then, slowly roll the laser and see if there is any suspicious movement in the red dot on your wall. It should not go up or down, but just sideways. You can also attach it to your telescope and rotate it while it is on while watching the dot on the mirror. The dot should not move at all.

Note that we are using our usual Orion Astrograph 8" f/3.9 telescope and our laser collimator is the Orion Lasermate Deluxe II.


Attach the laser collimator to the telescope, just where the eyepiece or camera would go. Make sure the target drawn on the device is facing towards the back of the telescope.


Start in the front of the telescope. This is where the secondary mirror is located. What you want to do is tighten or loosen the three tiny screws that are just in the middle of the spider vains.

How it works? Each screw, when being tightened, pushes the secondary mirror, giving it a different angle and so bouncing the laser a different direction.

The goal here is to center the red dot from the laser inside the small circle that is drawn on the primary mirror.

Make sure you do not tighten the screws too much or you will break the secondary mirror holder. It happened to us once and we had to completely replace the holder.


Last step (already, yes!).

Go to the back of the telescope. You do not need any tools for this, so put the screwdriver in a safe place and simply use your fingers.

Loosen the lock screws (long, thin) so that you are able to turn the three adjusting knobs (short, fat).

Those knobs work exactly like the screws behind the secondary mirror. Your goal here is to turn each knob until the laser is bounced back to the center of the bullseye, visible on the laser collimator. This is why it is important to attach it facing towards the back of your scope!

It can take a while at first, but it becomes easier and easier the more you do it.

You will know you did it right when the dot is completely eclipsed and not visible anymore.

Once that's done, secure the lock screws by tightening them. Be careful not to accidentally affect the laser angle.

That's it for this very short tutorial!

We hope this will help beginners collimate their telescope quickly and easily, so you can spend more time imaging :)

Take a look at the video below to see the entire process from our point of view!

Let us know if you have any questions or comments.


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Clear Skies,

Galactic Hunter

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