Building a DIY Telescope: A Fun Family Project
I’m the kind of person who prefers spending time with nature and exploring the wonders of space, rather than engaging in materialistic activities like shopping, cinema, or parties. I love to share this passion with my kids by involving them in hands-on projects like repairing broken toys, learning to use tools, and creating DIY projects. In this article, I’ll guide you through how we built our simple telescope at home.
Field Experiment is important!
The first principle in DIY projects is never to hesitate to failure. Experiment, fail, try, repeat, succeed, improve, and keep going.
Why Build Your Own Telescope?
If you’re curious about observing birds, treetops, or the night sky, building a telescope with your family can be a rewarding experience. A homemade telescope not only gives you a new way to explore the world but also provides a sense of accomplishment when you see the stars and planets through something you built yourself.
Small refractor telescopes are ideal for beginners because they’re light and portable, and their optics need little to no adjustment. Let’s dive into how telescopes work and how you can build one.
How Does a Telescope Work?
Understanding how a telescope works starts with its most crucial part: the objective lens. This convex glass lens is mounted at the front of the hollow telescope tube and is responsible for gathering light from distant objects. The light rays passing through the lens are bent (or "refracted") towards a point inside the tube called the principal focus. The distance from the lens to this focus point is known as the focal length.
Example: Imagine holding a magnifying glass under sunlight. The way it focuses light to a single point is similar to how the objective lens in a telescope works.
Choosing the Eyepiece
At the opposite end of the telescope is the eyepiece, which is positioned so its focus aligns with the focus of the objective lens. The eyepiece magnifies the image formed by the objective lens, allowing you to see distant objects more clearly.
Example: If your objective lens has a focal length of 400mm and your eyepiece has a focal length of 10mm, the magnification would be 400 ÷ 10 = 40x. This means objects appear 40 times closer than they do to the naked eye.
You can buy a basic 1.25-inch Plössl eyepiece for around Rs. 200, which is perfect for beginners.
Selecting the Right Lens for Your Telescope
The ability of a telescope to magnify faint objects has transformed astronomy. Even a small 50mm refractor can be a powerful tool. The first telescopes used a single convex lens, but modern designs use a doublet lens made of two different glass elements, called an achromatic lens. This design reduces color distortion (chromatic aberration) and produces a clearer image.
Example: You might notice cheaper lenses creating a colored halo around bright stars. An achromatic lens helps avoid this problem by bringing different colors of light to the same focus point.
Building the Telescope
Now, let’s get to the fun part—building your telescope! You’ll need some basic materials, most of which can be found at a hardware store.
Materials Needed:
PVC Pipes and Joints:
Segment 1:
50mm (ID) PVC joint - 1 piece
50mm (OD) x 500mm long PVC pipe - 1 piece
Segment 2:
40mm joint - 2 pieces
40mm x 220mm pipe - 1 piece
40mm x 25mm pipe - 1 piece
40mm to 25mm reducer - 1 piece
25mm x 160mm pipe - 1 piece
25mm joint - 1 piece
Others: 50mm joint & screw for mounting on a tripod, masking tape
Steps to Build:
Measure the Focal Length: Make a simple stand for the lens and use a sheet of white card to measure the focal length by projecting an image onto the card.
Tip: If the 50mm pipe doesn’t fit easily into the 50mm joint, heat the pipe’s end for 2-3 seconds and then push it into the joint. Be careful not to heat it with the lens attached, as this can damage the lens.
Assemble the Telescope: Using masking tape, assemble the PVC pipes and joints without glue for easy adjustments. Place the eyepiece at the appropriate distance based on your measured focal length.
Test and Adjust: Hold the telescope for terrestrial viewing or mount it on a tripod for stargazing. Slide the focuser in and out to achieve a clear focus.
You can notice that I used Lego building blocks to attach our DIY telescope to the tripod stand.
Pointing to the Stars
Once your telescope is assembled, you can start exploring the night sky. While you can hand-hold the telescope for daytime viewing, for stargazing, a tripod is highly recommended. You might also consider investing in a small altazimuth or equatorial mount for better stability and control.
Building a DIY telescope is not only a fun project but also an educational one. It’s a great way to introduce your family to the wonders of the universe. Happy stargazing!
