How to Make a Telescope: Tips and guidelines for beginners
This article will show you the complete process for making a small refractor telescope. I also have a video that goes along with this tutorial. The picture below shows the telescope that I make and that you can make too.
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.
Need lenses? These are the exact lenses I purchased for this project:
LENS DBL CONVEX 3.75CM DIAM 30CM FL (This is the objective or long focal length lens)
LENS DBL CONVEX 3.75CM DIAM 5CM FL (This is the lens I used for the eypiece, the short Focal length lens)
Want to make a bigger telescope?
New Project . I have started the 4 1/4" reflector telescope project. I made a temporary tube assembly to test it all out. Worked great. And now I have completed the tube assembly. You can follow along with that project here: How to make a Newtonian Reflector Telescope
Cardboard Galilean Style Telescope Building Kit
This kit can be supplied assembled or in pieces for young hands to construct as a fun learning tool. The kit comes with: (2) telescoping tubes (1) positive lens (1) negative lens (2) end caps and an instruction page. The telescope assembles in about five minutes and is ready to use. There is no glue needed, kit can be dissembled and reassembled. The magnification is approximately 3X, and the view is right side up. Ages 10 and up.
Make Your Own Refractor Telescope Kit
Using kit materials, students build a hand-held, 10× refractor telescope in a matter of minutes and start viewing the heavens as Galileo did in 1609.
Kit includes objective and eyepiece lenses, tubes and end caps, assembly instructions, viewing tips, and directions on how to measure focal length and calculate magnification power.
Galileo's Telescope Kit - Teacher Demo
Inspire eager stargazers to build, decorate, and experiment with their own 16-power refracting telescopes. 1 set of materials with instructions and activities.
Experiment with each element of a simple refracting telescope and see how the lenses work when put together without using an optical bench. Galileo's first telescopes lacked precision and clarity. Nevertheless, he made astonishing discoveries with his crude instruments. This simple lab enables students to build a telescope that is similar to Galileo's. Use the telescope and see how it is similar to a pinhole camera View inverted astronomical images Estimate the magnification power Find the focal length of a lens See how the moon looked to Galileo. Can be purchased in a bulk rate pack of 10.
Investigating & Building Refractor Telescopes Kit
Here is an engaging way to help your students explore how concave and convex lenses refract light to produce real and virtual images. Students measure the lenses' focal lengths and discover how lens pairs can be used to make 2 different types of refracting telescopes. From the determined focal lengths, students calculate their telescopes' magnification powers.
Kit includes instructions, activities, and materials to build 8 hand-held refracting telescopes (4 Galilean and 4 Keplerian), each with a 444-mm-focal-length objective lens and a 50- or 150-mm-focal-length eyepiece lens.
Note that amazon.com does have a nice little kit. I haven't tried it but it looks pretty good and includes the lenses
Make your Own Telescope complete kit with lenses
3X Refractor Telescope Kit - This fun learning kit includes everything students need to assemble a 3X power telescope based on Galileo's original 1690 design. -- Construction of the 18" scope takes less than one hour and is simple to complete. Once built, the telescope offers widefield viewing and easy zoom focus, with capabilities powerful enough to show craters on the moon, Jupiter's moons, and many stars invisible to the naked eye. -- Includes instruction manual, along with star and planet indicator, and activity cards.
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.
My telescope making project: I have begun a project where I make an 8" reflector telescope. You can keep track of the project and learn how to make your own here: Making an 8" reflector telescope
Making & Enjoying Telescopes: 6 Complete Projects & A Stargazer's Guide This is a relatively modern book on telescope making (Printed in 1995) and it takes a nice slant on the whole subject by giving you complete details on six different telescope projects ranging from a big dobsonian to a small rich field telescope. Good book and I have a more in-depth review of it here. Book Review of Making & Enjoying Telescopes