Tag Archives: Radio Astronomy

Scott Tilley (VE7TIL): The Amateur Astronomer Who Found a Lost NASA Satellite

Many thanks to SWLing Post contributor, Cap Tux, who shared a link to the following video on YouTube. This short video is brilliant and will be the reference I use when people ask about the intersection of radio and amateur astronomy:

Click here to view on YouTube.

Amateur astronomer Scott Tilley made international headlines when he rediscovered NASA’s IMAGE satellite 13 years after it mysteriously disappeared. In this interview with Freethink, Scott discusses his role in the satellite’s recovery, why he enjoys amateur astronomy, and how citizen scientists like him have contributed to our knowledge of space from the space race to the present day.

And I personally think our Post friend, Troy Riedel–who is an avid amateur astronomer–should start tracking satellites! (We’ll see if he’s reading this post!)

I’m curious: are there any Post readers who are into the satellite tracking side of amateur astronomy?

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Radio enthusiasts receive images from the Longjiang-2 in lunar orbit

Image received by astronomer Cees Bassa (@cgbassa) using the Dwingeloo Telescoop

Many thanks to SWLing Post contributor, Eric McFadden (WD8RIF) who shares the following story from The Planetary Society:

Earlier this week, on October 10, radio amateurs all around the world worked together to get the Chinese Longjiang-2 spacecraft to take an image of the Earth and the far side of the Moon. Radio commands were generated by MingChuan Wei in China, transmitted to the spacecraft by Reinhard Kuehn in Germany after which they were received by the spacecraft in lunar orbit. In turn, the spacecraft transmitted the image back to Earth, where it was picked up by radio amateurs in Germany, Latvia, North America and the Netherlands.

Since June this year, the Chinese Longjiang-2 (also known as DSLWP-B) microsatellite has been orbiting the Moon. The satellite is aimed at studying radio emissions from stars and galaxies at very long wavelength radio waves (wavelengths of 1 to 30 meters). These radio waves are otherwise blocked by the Earth’s atmosphere, while the lunar environment offers protection from Earth-based and human-made radio interference. Longjiang-2 was launched to the Moon together with an identical twin, Longjiang-1 (DSLWP-A), together acting as a radio interferometer to detect and study the very long wavelength radio waves by flying in formation in lunar orbit.

Besides the scientific instruments, both Longjiang satellites carry a VHF/UHF amateur radio transmitter and receiver (a transceiver) built and operated by the Harbin Institute of Technology (in Chinese). The Longjiang-2 transceiver also includes an onboard student camera, nicknamed the Inory Eye. The Harbin team built on experience gained with the Earth-orbiting LilacSat-1 and LilacSat-2 nanosatellites, which allow radio amateurs to receive satellite telemetry, relay messages and command and download images taken with an onboard camera.

While receiving signals from satellites in low Earth orbit requires only relatively simple antennas, doing so for satellites in orbit around the Moon (a thousand times more distant), is much harder. To this end Longjiang-1 and 2 transmit signals in two low data-rate, error-resistant, modes; one using digital modulation (GMSK) at 250 bits per second, while the other mode (JT4G) switches between four closely spaced frequencies to send 4.375 symbols per second. This latter mode was developed by Nobel-prize winning astrophysicist Joe Taylor and is designed for radio amateurs to relay messages at very low signal strengths, typically when bouncing them off the surface of the Moon.

[M]any radio amateurs have been able to receive transmissions from Longjiang-2. Usually, the transceiver is powered on for 2-hour sessions at a time, during which GMSK telemetry is transmitted in 16-second bursts every 5 minutes. After some testing sessions in early June, the JT4G mode was activated, with 50 second transmissions every 10 minutes.

Specialized open source software written by MingChuan Wei and the Harbin team enables radio amateurs to decode telemetry as well as image data and upload it to the Harbin website.

The JT4G mode has allowed radio amateurs with small yagi antennas to detect signals from Longjiang-2 (using custom software written by Daniel Estévez).[…]

Click here to read the full article at The Planetary Society.

This is fascinating, Eric!  Thank you for sharing. It would be amazing fun to grab one of these Lunar signals! Anyone up to the task?

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Ruby Payne-Scott: a pioneer in radio astronomy

(Source: New York Times via Howard Bailen)

Since 1851, obituaries in The New York Times have been dominated by white men. With Overlooked, we’re adding the stories of remarkable people whose deaths went unreported in The Times.

By Rebecca Halleck
Every so often our sun emits an invisible burst of energy.

This energy ripples through space as electromagnetic waves and then crashes into planets and meteors and space debris and one another, causing a great cacophony above and around us.

A cacophony that was inaudible, until Ruby Payne-Scott entered a laboratory.

In the 1940s, Payne-Scott helped lay the foundation for a new field of science called radio astronomy. Her work led to the discovery of deep-space phenomena like black holes and pulsars and later helped astronauts understand how solar storms disrupt weather in space and electrical grids on Earth.

Yet as a married woman she was denied equal employment status and compensation. She challenged the scientific establishment in her native Australia and fought for the rights of women in the workplace, but ultimately left science to raise her children full time.

World War II opened the door to Payne-Scott’s scientific career. The Australian armed forces needed physicists, and men were joining the military to fight instead.[…]

Continue reading the full article at the NY Times.

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Wired: The ngVLA and “Rebirth of Radio Astronomy”

The NRAO’s Very Large Array (VLA) in New Mexico is 40 years old.

(Source: WIRED)

IN THE EARLY 1930s, Bell Labs was experimenting with making wireless transatlantic calls. The communications goliath wanted to understand the static that might crackle across the ocean, so it asked an engineer named Karl Jansky to investigate its sources. He found three: nearby thunderstorms, distant thunderstorms, and a steady hiss, coming from … somewhere.

Jansky studied the hiss for a year, using a rudimentary antenna that looked like toppled scaffolding, before announcing its origin: The static was coming from the the galaxy itself. “Radio waves heard from remote space,” announced The New York Times in May 1933. “Sound like steam from a radiator after traveling 30,000 light-years.” Janksy had unwittingly spawned the field of radio astronomy.

Today, a replica of Jansky’s scope sits on the lawn in front of Green Bank Observatory, one of the four world-class public radio telescopes in the US. Along with the Very Large Array, Arecibo Observatory, and the Very Long Baseline Array (VLBA), it is the legacy of a boom time in federal investment in the field that began in earnest after World War II.

In the past several years, though, the National Science Foundation has backed away from three of those instruments. In 2012 the NSF published a review recommending that the foundation ramp down funding to Green Bank—just 11 years after it was finished—as well as the VLBA, which can resolve a penny from about 960 miles away. Three years later, the foundation asked Arecibo for management proposals that “involve a substantially reduced funding commitment from NSF.”

[S]upport for pure science in the US is always complicated, since it relies on the good graces of federal agencies and annual budgets. As funders balance building and operating new scopes with the old, while giving grants to the astronomers who actually use those instruments, something’s gotta give. And no matter what it is, the science will not be the same.

[…]THERE IS A new facility potentially on the horizon: The Next-Generation VLA (the VLA itself, while upgraded, is 40 years old). As currently envisioned, the ngVLA’s many antennas will together have 10 times the sensitivity and resolution as the VLA, at a wider range of frequencies. The primary array will have 214 18-meter antennas, spiraled across New Mexico, Texas, Arizona, and Mexico. Nineteen smaller ones will sit close to the center, and 30 18-meterers will constellate the continent.[…]

Read the full article at WIRED magazine.

Check out this video for more info about the ngVLA:


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A history of listening to Mars

(Source: Atlas Obscura via William McFadden)

When the red planet comes close to Earth, some people have tried to tune in to see if it has anything to say.

ON RECENT EVENINGS, AS JULY has melted into August, Earth’s rocky red companion has dropped by for a visit. Earth and Mars, when they’re on opposite sides of the Sun, can be as many as 250 million miles apart. This week, however, Mars has been just shy of 36 million miles from Earth, the snuggest our planets have been since 2003. Looming bright and orange in the night sky, it has been easily visible to the naked eye. The close-up comes courtesy of opposition—the point at which Mars, Earth, and the Sun align, with us sandwiched in the middle.

When the planets approached a similarly cozy distance 94 years ago, in August 1924, some people, including Curtis D. Wilbur, the Secretary of the U.S. Navy, thought it might be possible to actually hear messages from our neighbor. If Martians were ever going to drop us a line, they suspected, that’d be the time.

From an office in Washington, D.C., Wilbur’s department sent orders to every naval station clear across the country. An outpost in Seattle received a telegram asking operators to keep their ears tuned to anything unusual or, maybe, otherworldly.

“Navy desires [sic] cooperate [sic] astronomers who believe [sic] possible that Mars may attempt communication by radio waves with this planet while they are near together,” it read. “All shore radio stations will especially note and report any electrical phenomenon [sic] unusual character …” The orders asked for operators to keep the lines open and carefully manned between August 21 and August 24, just in case.


This request didn’t come out of nowhere. There was a long buildup to the idea that Mars might be trying to tell us something, with technologies that were then new to us.[…]

Click here to read this article at Atlas Obscura.

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