How to collimate a telescope?

(Last Updated On: March 18, 2018)

Collimation is a process through which we align the optics of our telescope to get the best focus through our eyepiece. In simple word, we can say it’s a process to align the mirrors of our reflector. Don’t worry, you don’t have to be an expert to collimate your telescope by yourself. If you understand the process clearly it’s not more than a work of 5 minutes.

Below is an easy 3 steps guide for you to collimate the telescope by yourself with the help of laser collimator.

Things we need:-

a) Allen key (usually supplied with your telescope)

b) Screwdriver (supplied with a telescope)

c) Laser collimator (must buy)

SVBONY Red Laser Collimator 1.25” Battery 7 Bright Levels Triple Cemented Lens Metal with 2″ Adapter for Reflector Telescope Collimation (24$ approx)

As the name suggest it can be fitted into both 1.25” and 2” reflector, comes with a lifetime warranty so don’t worry about the quality of the product.



Let’s get started:-

We already know our telescope has a three basic components Primary mirror situated at the bottom of the tube, Secondary mirror, and an Eyepiece(see above pic). To collimate the telescope we start with aligning the Secondary mirror first because it has more chances of getting out of alignment. Four screw are present in the back of Secondary mirror holder, three of them are side screw to control the tilt and the screw at the center is for controlling rotational and longitudinal adjustment of secondary mirror(see pic below).

Note- Always remember to put your telescope into a horizontal position before collimating. You don’t want your screw or something to fall on to your primary mirror and damage the product permanently.


Step1Using Laser Collimator



First, Insert the laser collimator into draw tube and remember to put the Collimator in such a way that the target area should face the primary mirror(as shown above in the picture,more on that in step 3). Now just lock the focuser and collimator tightly.



Step2- Adjusting Secondary mirror

After inserting the laser collimator you will notice that the focus of laser on primary mirror is not at the center(as shown in below picture). Now we try to move the laser to center by adjusting the three screw presented at the back of the Secondary mirror with the help of Allen key. After perfectly aligning to the center we just lock the mirror by tightening the center screw with the help of a screwdriver.



Step3- Aligning Primary mirror

Primary mirrors have a total of 6 screws. Three of them are Locking screw smaller in size used for locking the mirrors and another three are Adjustment screw  bigger in size used for adjusting the mirror( as seen in pic above, step 1). After inserting Laser collimator you will notice that reflection of the laser will be near the target area of collimator but not at the center.  Now to move that to center loosen up the locking screw then move the adjustment screw slowly to clockwise or counter-clockwise direction.



Once the laser is in the center (as shown above) of the target your telescope is perfectly aligned. Just tighten the locking screw in that position and you are ready to go.

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