How to Make a Telescope: Tips and Guidelines for Beginners

Making a telescope is an extraordinarily rewarding experience because it crosses several different realms of experience. The first reward for you is the fun of making something. And the second reward is the sheer pleasure of using what you made to explore the universe. And you also get the added benefits of saving some money and learning about telescopes and building things.

The Simplest telescope you can make

There are a lot of different types you can make and the absolute simplest one you can make is composed of just two lenses. One large lens called an objective and a second smaller lens called an eyepiece. You hold one lens near your eye and another lens at arms length. You adjust the difference between the two by moving your arm in toward you.  A point will be reached where everything comes into focus.  It is as simple as that. You have a telescope.  Now you can make it much better by creating a tube around it. Get two cardboard tubes with one that can slide in and out of the other. You mount one lens on the end of one tube and the other lens on the end of the other tube.  Insert one tube into the other and then slide them in and out to find the focus.  

You can get very inexpensive lenses from a variety of surplus and online stores and they generally will only cost a couple of dollars each. I recommend you get for your primary lens a convex lens at least 50 millimeters in diameter and a focal length of between 200 and 300 millimeters. For the secondary lens I recommend you get a convex lens that is between 10 and 25 millimeters wide with a focal length of less than 75 millimeters.

There are several things you can do to make this telescope even better. First off you could make a tube out of something more durable than cardboard tubes.  Secondly,  this type of telescope will invert images so everything appears upside down which is ok for viewing the sky but is very awkward for viewing things on the earth. You can solve this by using a concave lens for the eyepiece rather than a convex lens.

You can purchase the lenses individually from online surplus stores and there are several kits readily available that give you all the necessary materials to make this kind of telescope. They also come in bulk units for classroom and group use. A kit like this typically gives you all the materials needed to make ten or more telescopes.

Getting A little more involved with your telescope making

If you want a bit more of a challenge you should consider making some type of reflector telescope. Instead of a large objective lens as the light gatherer this type uses a mirror.  A reflector can be very economical by giving you great price versus performance. Mirrors cost substantially less than lenses so for the same amount of money spent you can get a much larger and much more powerful telescope.

If you have a bit of woodworking or metal working skill and you want to tackle a project that is well within the means of a hobbyist you might want to consider making a Dobsonian telescope.  A Dobsonian telescope uses a parabolic mirror to collect the light and most Dobsonian builders buy the mirror then build the mount for the mirror to go in. The basic concept of this type of telescope is that it is easy to build and easy to use. It is pretty much just a rotating base with a telescope tube mounted on it. And this type of instrument has gotten very popular because it really is easy to use and easy to build. And one of the biggest benefits is that because it is so inexpensive to build more money can be spent on larger mirrors which can make them quite remarkable in terms of their ability to see things in the night sky.  If you are considering making this type of scope you probably should begin with one that has a mirror between six and eight inches in diameter.

Whether you build a refractor or a reflector telescope making is a very rewarding pursuit and is something you can enjoy for a lifetime. And once you start you might find that you have caught the fever and will be always looking toward building bigger and better ones.  For some people making them is half the fun.

 

 


Will Kalif
About the Author:

The author has been an amateur astronomer for many decades. Learn more about telescopes and astronomy by visiting his website at:

TelescopeNerd.com

You can see drawings and more explanation of making a simple refractor telescope by visiting his tutorial at: Make a simple Refractor

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