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How to Use a Dobsonian Telescope? 5 Simple Steps

Doesn’t it bother you when you can’t use a Dobsonian telescope though you have one? Well, you might hate the difficulties that you have faced while starting to use it. No more worries. Take a breath, pick yourself up.

 This article is for you if you are a new astronomer looking for the ways to use a Dobsonian telescope. This can also be a refresher article for you if you are just about to restart your visual observation after forgetting how to do it.

So Don’t let the troubles resist you from enjoying the celestial journey. Let the journey be easier and fairer conquering your troubles.

Here is a little piece of information to make you understand more about a Dobsonian telescope before going through the methods of using it. Let’s know it first.

What is a Dobsonian Telescope?

How to Use a Dobsonian Telescope

Dobsonian telescope is a reflector telescope using an altazimuth mount named Dobsonian. John Dobson, An American astronomer first designed it and he was credited afterward for popularizing its design. This design shows the style of the mount that uses the same two-axis mount.

  1. The azimuth axis (horizontal) 
  2. The altitude axis (vertical)

Dobsonian telescope is also called a Newtonian telescope as it’s based on a Newtonian reflecting tube. And now it’s well known as a larger, compact, low-cost and simple telescope.

Simple Steps to Use a Dobsonian Telescope

Using a Dobsonian telescope isn’t as difficult as you think. You can simply use it if you know the very basics of it including every piece of relevant information. And here we gathered those pinpoint details for a clear understanding. 

Think about it, you are using your Dobsonian telescope without a computer or a motorized device. Won’t it be easier for you in this way? So this can be the perfect place for you to have a quick and good starting. Just follow the steps we described below.

1. Get an overall view

Look at the picture. That tube of blue color on the mount is called OTA or Optical Tube Assembly. It’s not just a piece of equipment, rather a combination of several pieces. So first you need to check the OTA if there is anything missing or any part broken, especially check the primary mirror on the bottom of the tube and the secondary mirror located near the top of the tube. This picture given below will make you clear about the mirrors.

2. Assemble the telescope

Now you need to assemble the components of the OTA. Place the tube into the mount and Assemble the other parts of the tube. To make you clearer, the assembling parts are given below:

A small device or auxiliary telescope to help the targeting point be more accurate. This device will allow you to locate the objects of your target.

This tube controls the eyepiece holder to move up and down slightly and adjust the eyepiece to every individual observer.

  • The base

Make sure that the base you are using for your telescope is okay and can swivel.

  • The control knobs

The control knobs should turn without any difficulty. Make sure that they can lock the vertical axis.

Check whether your eyepieces or visual lens are not broken and definitely clear. This lens is placed closest to the eye when you will be looking through the device. And your eyepieces will magnify the images created by the objective mirror.

3. Collimate the telescope

Wondering about this step? is the question, “What is collimation?” appearing in your curious mind? No difficulties. We will make you clear about the whole process.

What is collimation?

Collimation is the process of aligning the components to make the best focus. To be more specific, collimating your telescope means adjusting the primary mirror and the secondary mirror by using the control knobs.

You will find fixed primary and secondary mirrors in some telescopes. If you have one of those, you can carry the mirrors anywhere you want to go. You can even throw them in the back of your car for transport and they will remain in place. And in this case, you won’t have to collimate frequently.

On the other hand, if your telescope is sensitive and tends to have bumps, you should collimate it before each use.

What’s on your mind now? Let me guess. You are worrying about how to do it, isn’t it? Okay, you can collimate your telescope just by following these three easy steps:

Step 1: Place your secondary mirror to the middle on the axis of the focuser tube.

Step 2: Make your eyepiece aimed towards the center of the primary mirror.

Step 3: While viewing through the eyepiece, aim the sweet spot of your primary mirror and place it at the center.

To know the process more elaborately, click here.

4. Align your finderscope

You will get a low magnificence view of the sky by using your finderscope. And if you can perfectly align your finderscope, you will be able to direct your telescope towards an object and quickly observe the same object you are interested to see. 

As the finderscope is separately mounted, there is a chance that the device can move out of alignment while carrying. So you need to align your finderscope. To learn the basics of aligning your finderscope, follow the three simple steps given below: 

First, Fix your target. Pick out a stationary or a distant object such as a light post or the top of a distant telephone pole. Try it in daylight so that you can easily see the object. 

Second, Pick a low-power eyepiece (23 millimeters) from your package. Now keep it into the star diagonal.

Third, Centre the object in your eyepiece and turn the two adjustment knobs until your target object is centered. 

The alignment is done. Your finderscope is ready to observe. Now move your finderscope by the alignment screws, target the object you want to see, and enjoy your observation tour.   

Things to keep in mind:

  • Make sure that your base is correctly leveled. The azimuth axis doesn’t have a locking mechanism. When you will go to slightly locate your telescope in a tilt like in a slope, the heavier part of it can fall to the bottom of the slope.
  • Remove the dust caps from the OTA and the finderscope. It’s just a reminder because you may skip this step.
  • Sometimes, there are dark dust caps even at the bottom part. In this case, probably you won’t realize their existence as they can hardly be seen. So keep it in your mind.

5. Observe through the low-powered eyepiece

Low-powered eyepiece? Got confused? No more confusion. Here, by the term ‘power’, we meant magnification. To observe through the low-powered eyepiece, go through the steps given here:

  • Check whether your eyepieces have an X beside them.
  • Choose the lowest numbered one among them all.
  • If you don’t find an X, you will definitely find the eyepieces in millimeters.
  • In this case, select the one containing the highest number. It should be 23/24 millimeters.
  • Take the eyepiece you have selected and insert it into the focuser tube and lock it.
  • Now you can enjoy sharp images and you just need to turn the focuser knob.

Note: If you wear glasses, you may face troubles as you can’t reach the focus for the distance between your eyes and the surface. So what’s the solution? Just look at the eyepiece and check whether there is a rubber shield around it or not. If you find one, you need to fold it away. Thus you can be closer to the eyepiece in spite of having glasses on your eyes.

Things to Remember Before Using a Dobsonian Telescope

Suppose, you have followed the steps and are ready to start your telescope tour. But still, you are facing troubles while going to start using the Dobsonian Telescope. It will bother you for sure. So we have arranged this segment for you so that you don’t have to suffer from anything while starting out from the very beginning. Just remember some specific things:

  • Start your telescope journey by observing the bigger and brighter objects such as the moon. 
  • As the earth rotates, it will be an obstacle while you will observe an object. If you use a high-powered eyepiece, it will make the objects quicker to drift away. So, skip the one with high-magnification. 
  • Use low-magnification eyepieces and thus you can observe longer only by adjusting the alignment knobs.


Let’s see in brief what we talked about in this article. We defined what a Dobsonian telescope is, described the 5 easiest steps to use yours one, revealed some specific things to keep in mind, and recommended several acts to do before using one. Now you can start using the one you possess. 

So if you have any queries or any curiosity to know, ask us. If you have something more interesting and beneficial, inform it too. We would like to add more tips and tricks from you. Give your review in the comment section and let us know your opinions. Enjoy using your Dobsonian telescope and the celestial observation.

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