10 mins read 23 Nov 2019

Community Science Project: DIY Radio Telescope

Join our citizen science project to build backyard Radio Telescopes that can detect the arms of the Milky Way Galaxy.

3 home-created horn antennae all lined up on their wooden stands. The antennas are pyramid shaped cones, that connect to a metallic square rectangle at the apex.
DIY horn antennae used for radio astronomy. Credit: Hackaday.

Project Summary

This DIY radio telescope project is the first of our #InspiringNextGen series and is all about getting people across Australia and NZ involved in science and the Australian/New Zealand space communities. There’s a bunch of info about this community science project below, including how to sign up and a little about the science at the bottom, but here’s a high-level summary:

  • We’re building a do-it-yourself radio telescope, and want you to also join us by either building your own, joining a team or following our journey
  • This is a fun science project that is open to everyone and you don’t need a technical background. Young people will need adult consent though
  • We expect the project to take 3 – 6 months, which includes building the telescope over the first 3 months and then collecting good data over the last 3 months
  • Time commitments are roughly 3 hours per weekend (2 for building / 1 for participating in online discussions)
  • We’re providing a Slack community that anyone can join into (safe space community rules apply)
  • We want to get fun, learning, science data, a better understanding of radio astronomy and documentation out of this experiment. It’s 100% ok if we don’t succeed, as long as we learn along the way
  • Sign up by emailing us below!

Who Can Participate?

This community science project is open to everyone who wants to participate. You’ll be participating from your own location and just checking in with the wider group on how your build is going. Our Slack channels will only be available to people in Australia and New Zealand, but we are happy to send you the instructions if you are overseas and want to tackle this yourself as well (and share results with us). 

This community project is a bit of a fun, science project – so it’s open to people who have zero experience in science – who can learn about radio telescopes, and through to experts like engineers and radio astronomers, who can provide guidance and support.

Young people are especially encouraged to participate but will require adult supervision as there are some aspects of purchasing and building (so using scissors, glues, etc.).

What is Required of you?

There are two ways you can join this community science project, these are outlined below.

When you join a team, you’ll be working with someone who is building their own telescope. So you’ll get to ask questions, watch the build, help do online research, share your knowledge and join the conversations.

The second option requires a little more commitment in time and resources. Here, you are building your own radio telescope and hosting/leading the team in your region. You’ll be required to fund the cost of materials (we estimate about $300), set up a time for your local community to attend meetings, report of your results and share your knowledge.

There is no entry-level of pre-knowledge required for this project, we’re all starting from scratch and learning along the way (which means it’s very much ok to fail and learn). Of course, instructions will be provided on the build and the community can share its knowledge with each other.

Diagram showing feed horn design which has labels for all axis of the pyramid structure, and calculation formula. Also second Box diagram with labels for height vs. width. This is the wave guide schematic.
We’re going to work out the schematics of our telescope and the best way to capture radio waves from space.

How's it going to work?

We expect the project to take about 3 – 6 months, depending on any curve balls we learn about along the way. The build itself should only take a few months, but the collection of good data might take longer, so we’re in no rush. Instead, we’re here for the learnings.

We’ll be committing 2 hours per week (on a Saturday) for our team’s work – which includes shopping for materials, building time, researching, testing, etc. On top of this, we are also committing 1 hour per week (also on the weekend) to participate in online discussions and share knowledge from our experiences.

When is it all going to happen?

We’re opening up the invitation period from today until 13th December 2019. This is where you can sign up (see below) and let us know if you want to join online, join in-person or host your own team.

Then on the weekend of the 14th and 15th December, we’ll be setting up the online chat rooms (using Slack) for the teams and introducing everyone to each other. This is the start of the project build period, which will run for approx. three months.

We’re aiming for ‘first-light’ (when our telescopes see data) after this weekend, around 14th March 2020, and have set out three months (until Mid-June) to be able to get good data (which means it’s not just noise but science data)

Graph showing Decibels vs. Megahertz, and peaks where galactic arms are.
Detections of Hydrogen gas emissions from the Galaxy. Credit: David Schneider.

How we'll Communicate and Collaborate

We’ll be setting up a Slack community (Slack is an online collaboration platform, with free sign-up) that teams and participants in our community science project can chat on. Here, you’ll be able to receive building instructions, ask questions, share links, share progress photos, share your knowledge and research and provide advice and tips.

With your permission, we’d also like to share your photos on the Space Australia website and social media platforms (Facebook, Instagram, and Twitter).

As with all online communities, we are building a safe, non-toxic space – so any harassment, bullying, intimidation or any form of discrimination will mean immediate expulsion from the project. It’s ok to respectfully disagree on the science (with evidence!), it is not ok to personally attack others. Remember, some people in our groups might be experts and others beginners - so patience and explaining things out in easy to understand language is key to good communication here.

What do we want to get out of this experience?

There is a wide range of things that we want to get out of this community science project:

  • Fun, enjoyment, a sense of community (priority 1)
  • Astronomical science data and experimental science results by tracking the movement of the Milky Way Galaxy
  • People from all walks of life learning about radio astronomy and radio telescopes
  • A working radio telescope would be good!
  • Collaboration and participation from everyone
  • Documentation - we’ll be putting together our document-as-you-build instructions and publishing this on the website so that anyone can take up this project in the future
  • Lastly, we want everyone to know that this is all about experimentation and it might not work! Some teams might have telescopes that work well in three months, and others not at all in six months. This is not a competition, this is a learning experience. If you come out of this with better knowledge about radio astronomy and radio telescopes – then we’ve achieved our goal!

How to Sign Up

Super simple – send us an email to with the following info:

  • Name
  • Town/City
  • Best email address (we will use this to invite you to the Slack community)
  • Are you wanting to Build a Telescope (i.e. host a team); or
  • Are you wanting to join a team

There’s also some other info we might need from you:

  • If you are a part of any astronomical associations or amateur astronomy clubs
  • If you are an expert in radio astronomy, engineering or amateur radio and you want to provide your expertise as part of this project (like an online mentor)
  • If you’re under 15, you’ll need to have your parents send us this email

Follow Our Project

Even if you don’t want to get involved as outlined above, you can still follow our project by looking out for our shared posts on social media using the tag #SpaceAusScope. Here’s our accounts:

And if you’re interested in running a community science project with us, email us at

The Science

Diagram highlighting several comparissons of the EM spectrum, going from lowest wavelength in the left to highest in the right. The first is a bar graph indicating if the wavelength penetrates Earth’s atmosphere. The second is a set of diagrams indicating the size of each wave relative to everyday objects. The third indicates the frequency and the last indicates the temperature.
Properties of the EM spectrum. Credit: Inductiveload.

Radio astronomy is the study of objects, events, and phenomena in space using radio waves, which make up part of the electromagnetic (EM) spectrum.

Due to their long wavelengths, radio waves can enter Earth’s atmosphere and pass through clouds, which means we can do radio astronomy during the day and even when it is cloudy.

The telescope we are building is a horn antenna, which is tuned into picking up small radio waves of 21cm wavelength. The source of these radio waves is from the most common element we find in the Universe, Hydrogen.

Massive Hydrogen clouds are found across our Galaxy’s spiral arms. This is the material that eventually forms stars, planets and everything else we see around us. We can’t see these cold interstellar clouds in optical telescopes, but we can with radio telescopes. To understand how we need to look at some atomic-scale science.

Hydrogen, as an atom, is fairly simple – it contains one Proton in its centre (which carries a positive (+) charge) and an orbiting electron (which carries a negative (-) charge). Let’s pretend that both the proton and the electron are spinning balls with their axis both pointing upwards

When this atom is most relaxed, or in a ground state, the two-axis are in opposite directions – so the proton points up and the electron points down. However, sometimes the electron gets an energy kick, which takes it to an excited state. When this happens, the electron has absorbed some energy. But it is no longer relaxed and really wants to get back to its relaxed state (don’t we all?).

To do so, it has to release the energy it absorbed back out into the Universe. And so the electron gets rid of the energy and reverts back to having its axis pointing downwards relative to the proton, which points upwards.

Now that little package of energy it released is a radio wave and it has a wavelength of 21cm. This travels across our Galaxy and eventually is picked up by the telescope we are building.

Diagram showing basic hydrogen atom in 2 states. Top diagram is excited and shows both proton and electron with axis in same direction. Bottom diagram shows the electron flipping its axis and facing down. Coming off the electron is a wave labelled 21cm.
Hydrogen spin-flip. When F = 1, Hydrogen is excited and wants to relax. It gets rid of some energy by flipping the spin of the electron, and then F = 0. Credit: Tiltec/Wikipedia.

By looking for 21cm wavelength radio waves coming from the Galaxy, we will be able to tell where the huge clouds of Hydrogen are and if they are moving towards us or away from us. This paints a picture of the Galaxy’s spiral arms through our data.

We’re hoping by collecting our data from the end of March and through to June, we’ll be able to capture an arm of the Milky Way and then the centre of our Galaxy, which usually is high in the sky by the middle of the year.

Illustration of the Milky Way, almost edge on. The spiral arms are labelled.
Illustration of the spiral arms of the Milky Way galaxy. Credit: NASA/Chandra.