How to Make a Telescope With Two Convex Lenses

It had been a popular query that- How to make a telescope with two convex lenses? 

But the answer isn’t that much widely available. 

The answer is a simple process, to be honest. Most high school kids might even try this as their science fair project. But this simple process is a bit hard to find. 

You can make a Keplerian telescope with two convex lenses. Moreover, you can do this at home. You won’t need much other than two convex lenses.

This telescope is great for seeing things on earth. To be more specific your telescope will be a refractor telescope.

Moreover, that won’t be a professional one too. So, it’s completely okay if you want to make this for fun and based on curiosity. Just don’t try to watch the sun or star with this telescope. 

So, let’s jump right into the details-

Step 1: Prepare Lenses

If you already have lenses, then it’s great. But make sure that one lens is bigger than the other. 

If you order up lenses, then it’s great. But you can make lenses too. 

You see convex lenses are nothing other than a thick glass curved in one direction. More like, curved outwards. 

So, how to make telescope lenses?

We’ll go through the process in a bit. At first, let’s clear out some details. 

As you’re new to lens making, you should take a bit thick glass. Thin glasses may break due to inexperienced pressure. 

Also, find out a coldworking glass studio near you. And don’t forget to gather up some stuff for the lens making. Safety stuff like mask, apron, and plastic boots are recommended for this job. 

Now that you know what you’ll need let’s get to the steps-

  1. Use a sharpie marker so that you can trace the place where you’d want your lens to be. 
  2. Draw a slightly smaller circle than the glass body to avoid carving up the outside. 
  3. Turn on the grinder and open up the water dripper. This water dripping will reduce thermal shock. 
  4. Push the glass towards the grinding wheel and follow the drawn circle. 
  5. Keep your grip on and control the grinding. Don’t let go when the grinder pulls the glass closer to it. 
  6. Make the ground part shiny by using the felt wheel.
  7. Add water and Pumice on the felt wheel to create an awesome shine. 

After these 7 steps, your lens will be ready. And if you somehow manage to get the grinder and felt wheel to your home, then you can make a homemade lens. 

Just make sure that your primary telescope lens is a convex lens 50 mm in diameter and has 200 – 300 mm focal length. 

For the secondary lens, make sure you have a 10 to 25 mm wide convex lens with a focal length of 70 mm highest. 

Step 2: Prepare the Telescope Body

Get two corrugated paper sheets and make two cylinders with those sheets. But keep the radius different. Just make sure that one cylinder can slide inside another cylinder. 

Use tape while building those cylinders. 

An easy way to build the telescope body is by making the paper cylinders by wrapping around the lenses. Just put one lens on the paper sheet and start rolling it around the lens. Once the paper wraps your lens completely cut the rest of the paper. 

Or you could measure the circumference of the lens and prepare a paper sheet of that width. 

After making the cylinders, comes the hard part. Now you have to insert the lenses into the cylinders. 

Cut a section of your cylinder and insert your lens through the cylinder. 

Now you’ve got two cylinders with two lenses on those. 

Step 3: Set up the Telescope

Now that your cylinders are completely ready, you can slide one inside another. But there’s a slight problem at this stage. 

One of your cylinders is 25mm in diameter and the other one is 50 mm in diameter.

So, you have to make up the space between those cylinders. You can create a paper circle of 50mm diameter with a hole of 25mm inside it. 

Glue it at the open end of the fat cylinder. 

Next, insert the open end of the small cylinder through this paper circle. 

Now you have your own telescope. 

However, this is not a powerful telescope. And you obviously cannot stargaze with this telescope. 

Bottom Line

Once you finish up the whole project, you’ll feel happy from the inside. The working mechanism of this telescope is simple but it’s pretty hard to make it. 

Pat yourself on the back after finishing it up. By the way, this can be an excellent gift for someone special. After all, you made it all by yourself. 

Good luck! Happy exploring!

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