How To Build A Telescope

Interested in learning more about the night sky and space in general?

Having an awesome telescope is a great way to see firsthand the wonder of space with your very own eyes!

But, it can be a pretty pricey investment to get a shiny new telescope. But don’t let that stop you from seeing the wonders of the universe!

How To Build A Telescope

What would you say if I told you that you can build a telescope from scratch with a few items that you’ve got lying around at home?

That’s right, with just a few bits and bobs, you can build a rudimentary telescope that will give you a cool look at the night sky!

Telescopes are great tools for observing celestial objects such as stars, planets, galaxies, and nebulae.

They also allow us to see things at much greater distances than our eyes alone can detect.

How Does A Telescope Work?

A telescope works by using lenses to refract light coming into them.

This allows us to magnify distant objects so that we can see details we couldn’t see without the help of a telescope.

The most common type of lens used in telescopes is called a spherical or convex lens.

These lenses bend incoming rays of light so they travel along parallel paths.

This results in images being formed on the other side of the lens.

The size of the image depends on how far away the object is from the lens.

To make the image bigger, we need to put the lens closer to the object.

By doing this, we increase the angle between the lens and the object. As a result, the image gets larger.

We can do this until we reach a point where the image becomes too big to be seen.

At this point, we have reached the focal length of the lens.

Super Easy Mode

Super Easy Mode

If you are looking for a really simple and quick way to see the night sky in better detail, try this method!

By using a window in your home, a cardboard tube, and a clear piece of glass that fits at the bottom of your tube, you can make a simple telescope!

You can easily build your telescope using only basic materials.

All you need is a clear piece of glass that has a curve to it (for our make-shift convex lens), a clean, slightly curved window to act as your other concave lens to attach your tube to, and a large cardboard tube with a flush bottom.

Once you have these items, you can start assembling them!

CAUTION: When using glass, be careful to not use anything with sharp edges, especially near your eyes!

A glass jam jar lid or any other curved and polished clear glass make a great makeshift lens, though you can always purchase a glass lens too!

Step 1: Cut The Cardboard Tube

Draw a hole on the bottom of your cardboard tube that is the same size as your circular curved piece of glass.

Carefully cut out a hole, making sure that your glass fits snugly inside!

Secure your glass tightly with tape, making sure there are no places the light can escape from.

Step 2: Line Up Your Tube To Your Window

Point your cardboard tube towards the sky on your window, make a line on your tube with a pencil so that the cardboard tube points to the sky and is flush with the window.

Cut the line, test the tube against the window- it should lie flush in the direction you want.

Step 3: Attach The Cardboard Frame

Now that you have cut your tube to lie against the window whilst looking at the sky, attach it to the window using tape.

Make sure that the edges of the cardboard tube are flush against the sides of the window. This will ensure that no light gets in or out.

You can also add a layer of aluminum foil on top of the cardboard edges to prevent any stray light from entering through the window.

Step 4: Take A Peek

Turn off the lights in your room, wait until nightfall on a clear night and place your eye against your lens.

You should be able to see a whole host of stars up in the night sky, much clearer than you would with your eyes!

Step 5: Add More Telescopic Lenses

If you want to increase the magnification power of your telescope, all you need to do is buy more lenses.

These can be purchased online or at local stores. Just remember that the larger the lens, the better the image quality.

Whilst this is the easiest way to do a DIY telescope, you may not have a curved window in your home!

Or if you want the freedom to point your telescope across the whole night sky, you may want to try out a different design!

Medium Mode

Medium Mode

Using some old round reading glasses lenses, you can have a go at making an easy and portable telescope to look at nature, animals, and the night sky!

You will need:

  • Two empty kitchen towel cardboard tubes
  • A pair of scissors
  • Tape
  • 2 convex lenses (round-rimmed lenses popped out of a pair of reading glasses works well, though if you want to buy better quality lenses from a specialist shop, you’ll get a much better range of magnification).

Step 1: Pick one of your tubes to become the inner tube. Cut that tube lengthwise, all the way up to the top.

Wrap one edge of the sides slightly over the other edge and hold it in place.

Step 2: Insert one end of the cut tube into the open end of the other paper towel tube so that they’re fully inside each other.

Let go of the tube so that it can be expanded inside the outer tube.

If the inner tube doesn’t slide smoothly, remove it and tighten the edge slightly.

After that, reinsert the inner tube inside the other paper towel tube so that it’s just right.

Step 3: Use masking tape to secure one of the lenses onto the outer edge of the inside tube.

The curve of the glass should face the inside of the tube, not the outside.

Step 4: Secure the second lens to the outside edge of the second tube with the curve of the second lens facing outwards.

It’s OK if you have larger lenses than the tube, just tape only around the rim of the lens, so you don’t cover any more than necessary.

Step 5: Put one eye up close to the lens of the inner tube. If you can see through the lens, then you’re ready to go.

Use a telescope to observe faraway animals, tall trees, or even stars. Never use a telescope to look directly at the sun.

Difficult Mode

If you’re after a bit more of a challenge, try making a DIY Dobsonian telescope!

The Dobsonian telescope is one of the most popular types of telescopes because of its ease of construction and portability.

It consists of a tube that holds the optics and the mirror assembly. The tube is supported by a base called a mount.

The mount is attached to the floor or ground via an equatorial mounting system.

The tube itself is usually made from wood, plastic, or metal tubing.

The optical elements include a primary mirror, secondary mirror, and eyepiece.

The mirrors are typically flat, but some models have convex (outwardly curved) mirrors.

The eyepiece is mounted directly onto the tube. The mount allows for easy movement of the telescope while observing objects.

This method of course requires you to find some more specialized parts, but you can customize it pretty easily to your budget or to how strong you want your magnification to be!

It’s worth having a search among the many instructions online from amateur astrologers that go into serious depth about how you can make the most of your budget and create some pretty awesome designs!

They are a bit too in-depth to go into here and require a proper workshop and some wily thinking to get right, but there’s a whole host of ideas to get your teeth into!

Final Thoughts

We recommend having a look at some cheap beginner telescopes if you’re looking for a great introduction to telescopes and astronomy, however, making your DIY version is a great project!

It can show you firsthand how light refracts, how you can magnify an image, and you can adjust all of the elements such as the lenses to suit any budget!

Gordon Watts