One Astronomer's Noise

I’ve been starting to see more and more questions about how to get started in amateur radio astronomy over the last few months. So, I figured it’s about time I sit down and lay out some options for you to try!

What is amateur radio astronomy?

First off, the word “amateur” as it is commonly understood to mean “unskilled,” is a totally not what I mean when it comes to astronomers. So many amateur astronomers are not just GOOD at observing the night sky, but way better at using a typical commercial telescope than those of us lucky enough to get paid to do it! It really reflects the more traditional meaning of the word amateur, as in “someone who pursues an activity for love, not a living.”

The vast majority of amateur astronomy is optical. Makes sense, right? We see things that give off visible light, and viewing astronomical objects by eye is extremely rewarding. Humans used only this type of light to study the night sky for millennia. But, it’s not the whole story when it comes to observing the Universe.

Astronomy is now a multi-wavelength, or even multi-messenger, discipline, meaning that there are other ways to observe what’s in the sky beyond just visible light. Radio waves, the lowest energy form of light, are something that we use every day for things like WiFi, Bluetooth, and, uh, the actual radio you might still listen to in your car. It’s something we all have at least a little bit of familiarity with. Additionally, radio waves from astronomical objects can penetrate the Earth’s atmosphere like visible light does. (Most other forms of light are absorbed by the Earth’s atmosphere, so observing those must be done from high altitudes or space.) It’s not surprising then that radio astronomy became the second major modality of astronomy in the 1940s, and it’s also not surprising that this area of astronomy is growing among amateurs.

What gear do I need?

The most popular image of actually doing radio astronomy in the cultural consciousness probably comes from the same movie that inspired me to become an astronomer, 1997’s “Contact.” There, Jodi Foster’s character Ellie Arroway is listening intently through giant headphones with an array of big “satellite” dishes in the background. Many radio telescopes ARE dishes, though there are other types as well. And, yes, for all my shouting that “radio astronomy observes light not sound,” it’s okay to experience the data coming from such a telescope through sound. It may not be scientifically useful, but it can parallel the optical experience of putting your eyeball to a telescope. (A decade ago, I wrote about ways you can do this during a meteor shower for Science Friday.)

A dish is one way to get into radio astronomy. Have a spare satellite TV dish? They are incredibly easy to find. Ask your friends, or try your local freecycle or trash nothing groups. You can use one to make one of the simplest telescopes, the Itty Bitty Radio Telescope. At its most basic, you can “hear” how much radio emission comes from the Sun as opposed to the background sky. More sophisticated setups (like this and this) turn the dish into a proper instrument for measuring radio emissions from the Sun.

You don’t have to limit yourself to dishes, however. A horn antenna is a classic design that you can replicate inexpensively using the instructions from the CHART group. (That is, Completely Hackable Amateur Radio Telescope. Finally, a proper acronym!) There are also instructions and lessons on another horn antenna from a group of educators who participated in a National Science Foundation Research Experiences for Teachers.

Of course, I’m going to plug the project that I’m currently involved in, Radio JOVE. As far from a dish as you can possibly get, this uses one or two long copper wires to detect low frequency radio emissions from the Sun and Jupiter. This project had been engaging amateurs, educators, and students in hands-on radio astronomy for 20 years before I finally got my hands on a kit and some students rounded up to work on it. You can see the work of the group from the past five years on my recent iPoster! With the new, more sophisticated receiver, we’ll be ramping up efforts to engage new potential citizen scientists.

One of the main reasons for the surge of interest in radio astronomy is the “SDR revolution,” or the wide availability of good and cheap Software-Defined Radios. The fun little “circuit bits” of a traditional hardware radio receiver are replaced by software. Previously, amateur radio astronomy had a HUGE overlap with the ham radio community. (Okay, it still does.) However, the simple SDR set-up puts the radio receiving capability into the hands of people who otherwise may have no interest in ham or who may have been intimidated by the hardware requirements.

Where can I find other amateur radio astronomers?

There is one piece of advice that I always give people who want to start to get into optical astronomy: find an astronomy club! There, people will be welcoming and friendly and share their telescopes and all that good stuff. Unfortunately, that is not the case for amateur radio astronomy, though not because of the people. All the ones I’ve met ARE also welcoming and friendly and are thrilled to show you their set up, but there just aren’t really enough of them out there to have a full “club” in a small geographical region. There is, however, an organization called the Society of Amateur Radio Astronomers. So, though you can’t expect to walk up to an observing party, there is still a way to find folks with this same interest. I first met this amazing group when I was a graduate student working at the Green Bank Observatory in West Virginia. They were the most curious, interesting, and fun group of people that you could ever imagine sharing that wonderful locale with.

There is also a Facebook group called Amateur Radio Astronomy where people post a range of home projects from around the world. I’m not on Facebook much at all in general, but it is very active and full of pictures and data from people’s home set ups.

Final Thoughts

A few months ago, I came across a really fantastic article written by astronomer Emma Chapman about radio astronomy “returning to its roots” through amateur astronomy in an era when the telescopes used by professionals are massive international projects. It features the passage that taught me the true meaning of the word amateur, her experience meeting amateur radio astronomers, and “rogue radio astronomer” Aaron Parsons with whom I worked in grad school. It seems that our advisors did a very good job of instilling a love of the instrumentation, not just the results, in both of us when we worked on the modest-looking yet mighty PAPER.

If you’ve ever been wondering about amateur radio astronomy, I hope this gives you a few possible places to start. Some of my friends in grad school thought I was a bit odd for preferring radio to optical astronomy, and I just can’t explain WHY I do. Maybe it was that early formative image of Ellie Arroway after all? In any case, I invite you to join this growing community!