5 mins read 16 Jan 2021

The Wheelie Bin Radio Telescope

Inspired by the SpaceAusScope project, Kent Rogers built a backyard radio telescope inside a Wheelie Bin during Melbourne’s lockdown – and it’s already collecting excellent data from deep space, mapping the neutral hydrogen in the arms of the Milky Way Galaxy.

The Wheelie Bin Radio Telescope. Credit: K. Rogers.

Australian’s are well known for their ingenuity, innovation, passion, and commitment to having a go. From the famous (and frankly, rather useful) insect repellent Aerogard, the Aussie backyard icon the Hills Hoist to the development of Wi-Fi, now used by billions of people around the planet – it all came from Australia.

And now, we can add a special astronomy-related feature to this wonderful list – the Wheelie Bin backyard radio telescope. That’s right, a fully functioning, DIY-developed telescope that lives inside a Wheelie Bin and is being used to collect excellent data from across the Milky Way Galaxy.

Inspired by and working as part of the SpaceAusScope project, a community-science project run by, Kent Rogers from Melbourne utilised innovation in his design – taking a common Wheelie Bin and building it as the housing unit for the backyard radio telescope.

The idea is genius.

It’s a radio telescope that can be moved around to different locations on wheels and is weatherproofed, which means Kent can leave it outside in the backyard and not have to worry about the elements affecting it.

The telescopes being developed as part of the SpaceAusScope project are horn antennas designed to detect the neutral hydrogen line from across the Milky Way Galaxy – produced when electrons bound within hydrogen atoms flip their spin direction and release a photon in the form of radio light.

The horn antenna allows the incoming stream of these photons to be directed into a waveguide, which houses a small antenna that picks up the signal. This is then amplified and converted into a digital signal, before being processed by special software.

The objective of the SpaceAusScope project is to utilise everyday things from around the house, or local stores to build a functioning radio telescope – something everyone should be able to do, to participate in learning about and being involved in science and astronomy.

Like other telescopes that have been developed as part of our project, Kent’s horn antenna uses aluminium flashing, the waveguide is a 4-litre olive oil can and the antenna made from a straightened paper clip. All of this has been built into a Wheelie Bin which has also been mounted onto a constructed Alt-Az mount that Kent put together using timber and a moving dolly.

Seeing the Milky Way in Radio Light

The 1.42 GHz signal detected by Kent’s telescope, as the Milky Way came into view. Credit: K. Rogers.

The 1.42 GHz signal detected by Kent’s telescope, even during the day when the Sun was present. Credit: K. Rogers.

Once Kent had all of the construction completed and software installed, he started observing the Milky Way Galaxy during a two-day period over 31 July to 1 August in 2020 from his home in Melbourne.

Southern Hemisphere locations have an excellent view of the Milky Way centre (located between the tail of Scorpio and the teacup of Sagittarius), with these constellations high in the sky during this time of year.

What Kent’s telescope observed was the rising and falling of a small peak around the 1.42 GHz frequency – and indication that the beam of the telescope was detected the 21 cm wavelength photons emitted by vast clouds of neutral hydrogen gas that are distributed across the Milky Way, following its spiral arm structures.

Some of the beam directions (red and green) of Kent’s telescope, overlayed on an Illustration of the Milky Way Galaxy. Credit: K. Rogers.

This cold gas is the stuff that goes into forming stars in the galaxy – so by observing the rising and falling peak within the signal, these backyard radio telescopes can show us the region of the sky where this gas exists – where stars will eventually be born from it.

With the ability to point his telescope in numerous directions (as a result of the excellent Alt-Az mount that Kent constructed), his telescope was also able to look at different regions of the Milky Way – for example, some of his data shows the beam pointing towards the galactic centre, whilst others, it points away.

Remarkably, Kent was able to conduct some further science and measure the velocity at which the signal was moving towards or away from his telescope, determining the velocity at which the centre of the Milky Way, our Sun, and even the Earth is moving with reference to the observation. This is some extraordinary community science in action.

The SpaceAusScope

The 1-metre tall horn antenna of the Balmain team’s SpaceAusScope during construction. Credit: R. Mandow.

The SpaceAusScope project started in late 2019 and features a number of different teams across the country who are developing their own backyard radio telescopes using everyday household materials.

The teams, made of families, radio enthusiasts, amateur astronomers, school students, and observatory clubs each worked through their own designs, learnings, and construction, helping each other and discussing their progress on a shared community channel.

The project was halted in March 2020 due to the Coronavirus pandemic, with a few teams achieving some early results. The team will be restarting the project next week, re-engaging the teams to develop their telescopes and continue collecting data.

Read Kent’s guest blog on our dedicated site below.

Read Kent’s blog on our SpaceAusScope website