Why Collimate A Telescope? (Explained, With Tips!)

Once you get your first telescope, there’s simply no feeling like it. And let’s face it, when you decide to invest in a device like this — most of us do plenty of research first. That means that you’ve spent a lot of time reading about refractors, reflectors, their differences, and all of the various models. 

When it arrives, the first thing you do is to unpack it and proceed to assemble everything. There’s a positive giddiness in the air — the excitement can barely be contained until nightfall. As the dusk arrives, you go out to your backyard, spot your first targets, and then — frustration.

Do you find that you can’t acquire an image that’s as clear as you want it to be? Are the belts of Jupiter almost invisible? Is the moon missing its many detailed craters? Don’t worry, and don’t be angry — you haven’t bought a dud telescope. You’ve simply got to collimate it. 

Here’s why you need to collimate your telescope

You need to collimate a telescope to align its internal components so light is perfectly focused. All telescopes need collimation, but reflector scopes need it more often. Neglecting it won’t cause damage, but it will prevent clear observation. The two types of collimation (mechanical and optical) are independent, so you may need to do one with or without the other.

Why collimation is so important

We have to point out that collimation is crucial for every telescope owner

This doesn’t mean that your telescope is a bad one — this is something that needs to be done with every telescope at some point or another. On the other hand, the difficulty of the process varies between different telescope models.

If we had to find the closest analogy to other mechanical equipment, it would be the maintenance that you do to your car. Sure, routine maintenance isn’t something that most people enjoy and that’s not the precise reason why you’d want to have a car; however, it’s something that’s simply a necessity. From time to time, you have to perform an oil change, and you have to inflate the tires if you want the car to run perfectly. 

The same is true for collimation. And if you know how some people like to keep tinkering around their car and spend time under the hood even when there’s no real need for it; plenty of telescope nuts do the same for collimation. However, if you’re not a fan of telescope mechanics but simply want to use it — know that a majority of the optics can be set up in just a couple of minutes!

What happens if you don’t collimate a telescope?

If you’re a beginner in the world of telescopes, you may not realize just how delicate of a device this is. In the world of astronomy, you won’t get very far unless you learn to appreciate the preciseness and dedication needed to operate a telescope. The lenses found within are extremely sensitive, regardless of the type of telescope that you use. As a result, you’ll find that they need to be in an absolutely optimal working condition for the entire telescope to function properly.

With that in mind — if you don’t collimate your telescope at some point in time, you’ll simply find that its functionalities are deteriorating. You shouldn’t be afraid of this type of maintenance, as that’s something everyone learns to do. 

As time goes on and you don’t collimate, you’ll realize that you’re experiencing more and more trouble while you focus on objects in the deep sky. Also, if your lenses get scratched due to elemental damage or improper use, you will experience difficulties as well. 

Do all telescopes need to be collimated? Why?

All telescopes have to be collimated at some point or another, but at different intervals and for different reasons. For instance — a reflector telescope will have to be collimated far more regularly. In fact, you have to make collimation adjustments to these each time you set up the telescope in a new location. If you move to a new stargazing location, adjustments will have to be made. 

We should also mention that there are two basic kinds of telescope collimation — mechanical and optical. If you need to perform mechanical collimation, that will happen if the physical parts of your telescope aren’t properly aligned — if your mirror isn’t properly centered within a tube, or your secondary mirror suffers from misalignment. 

On the other hand, optical collimation means that you need to align the optical surface of the telescope to the focal plane in a proper orientation. Know that these two collimations are entirely separate — one can be needed without the other. 

Common collimation pitfalls to avoid 

There are a couple of beginner mistakes that most people make while they perform telescope collimation. First of all — if you’re adjusting the position of the secondary mirror, you need to be extremely careful while handling the small adjustment screws; gently tighten or loosen them. As you do this, you’re actually pushing the above mentioned secondary mirror and sending the laser inside into various directions. 

As you probably know, your goal here is to handle the screws in a way that makes the red dot align perfectly with the primary mirror’s circle. You may be tempted to tighten the adjustment screws a lot — don’t do this, because your holder for the secondary mirror might snap and set you back a lot. 

Also, if you perform laser collimation — make sure that the laser collimator points towards your telescope’s back. Then, aim your telescope at a clear wall. If you see the laser’s red dot on the wall — you haven’t adjusted the telescope well. 

Finally, one of the clear signs of collimation on refractors are stars that appear with bleeding edges. While this is true, know that it’s not always a sign that you need to adjust something — your telescope may simply be overheating. 

If so, let it cool down before you go any further!