Tag Archives: 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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Astronomers organizing to save WWV

As an amateur astronomer, I knew it was only a matter of time before the astronomical community became involved to save WWV.  Specifically, it’s a group of mostly amateur astronomers who observe and record occultations.

What’s an occultation?  It’s the term when a solar system object passes in front of, and blocks out a star.  Why is this important to observe?  Lunar occultations are the easiest to observe (if the star is bright enough, one can do a crude observation with binoculars or even the unaided eye).  But there is very valuable science to be had with smaller objects.  When a dwarf planet [like Pluto] or an asteroid – passes in front of, and “blinks” out or blocks the light of a star – measurements can be taken that reveal the dwarf planet or asteroid’s size/diameter.  We can even determine if an object is round/oval – or maybe cigar-shaped when multiple ground observers record and accurately time how long the star “blinks” (or if the star doesn’t get covered by the asteroid in some locations but does in others). Okay, that is Occultations 101 (if you are interested in learning more, see the link).

Credit: Upcoming occultation – showing the path where the occultation is visible – from IOTA: International Occultation Timing Association

Note 1: In 2017, amateur astronomers using a 3” telescope determined that an asteroid had a moon!I had a 3” telescope, back in the 1970s, when I was a kid!

Credit: Sky and Telescope Magazine & IOTA: the International Occultation Timing Association

Note 2: Multiple occultation observations involving the dwarf planet Pluto (and its next target – a “KBO”) are helping scientists navigate the New Horizons space probe (and to identify hazards) as it speeds through space to its next target – nicknamed Ultima Thule – beyond Pluto (on January 1st, 2019).

Equipment used to record and document these fleeting events (some graze occultations only last fractions of a second) requires – you guessed it – time stamped video devices.  Back in the old days before video and other advanced equipment, astronomers would sit a shortwave radio next to the telescope with a tape recorder to audibly capture & record the time signal with the observer noting the start/stop of the event (we’ve come a long way since then – time stamped equipment has advanced this from “approximately” to “exact science”!).

The main point of this blog entry: astronomers have been asked to sign the White House petition to maintain NIST stations funding. Sky & Telescope Magazine, if they haven’t already, will be posting an article with an interview that they conducted with one of the leading occultation observers that includes a link to the petition on their web site.

Let’s hope this momentum continues to build – and that it makes a difference!

Guest Post by Troy Riedel.

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Our Galaxy Expressed as Jazz

Rather than take pictures of the Milky Way, astronomer Mark Heyer decided to capture it in a completely different art form.

This amazing video is part of an article from Interesting Engineering  depicting the motion of the Milky Way translated into a musical score.

While most astronomers love capturing unique and stunning images of the Milky Way, one astronomer wanted to capture the galaxy in a unique way. Astronomer Mark Heyer expressed how the galaxy moves in the musical composition “Milky Way Blues.”

This is no Vivaldi’s “Four Seasons,” as the music isn’t simply inspired by the galaxy’s sounds; it is the galaxy’s sounds. The University of Massachusetts Amherst professor created an algorithm that transformed the data into a series of notes.

“This musical expression lets you ‘hear’ the motions of our Milky Way galaxy,” he says. “The notes primarily reflect the velocities of the gas rotating around the center of our galaxy.”

Heyer assigned notes to the atomic, molecular and ionized gases that can be found between the stars in our galaxy. He then gave different pitches, tones and note count to the velocity and spectra of each gas phase. For example, atomic gases were given an acoustic bass sound, molecular gasses got woodblocks and piano, and ionized gases became saxophone notes.

“Astronomers make amazing pictures, but they’re a snapshot in time and therefore static. In fact, stars and interstellar gas are constantly moving through the galaxy but this motion is not conveyed in those images. The Milky Way galaxy and the universe are very dynamic, and putting that motion to music is one way to express that action.” He chose to compose this piece using a pentatonic scale – with five notes in the octave instead of seven – and in a minor key, because “when I heard the bass notes it sounded jazzy and blue,” he said.

You can read more about this incredible process here.

Watch the video here.

Enjoy!

Robert Gulley, AK3Q, is the author of this post and a regular contributor to the SWLing Post.       Robert also blogs at All Things Radio.

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Image shows the extent of human radio broadcasts

Click to enlarge (Image credit: Adam Grossman of The Dark Sky Company)

(Source: Popular Mechanics)

Carl Sagan’s famous line from his 1990 speech about the Pale Blue Dot image—”Our planet is a lonely speck in the great enveloping cosmic dark”—is an understatement. We might consider our Milky Way, with its estimated 100 to 400 billion stars, a significant fixture in the cosmos. But there are some 100 billion galaxies just like it in the observable universe. It’s a daunting reality to consider when we’re thinking about the possibility of making contact with any intelligence that might be out there.

This map designed by Adam Grossman of The Dark Sky Company puts into perspective the enormity of these scales. The Milky Way stretches between 100,000 and 180,000 light-years across, depending on where you measure, which means a signal broadcast from one side of the galaxy would take 100,000 years or more to reach the other side. Now consider that our species started broadcasting radio signals into space only about a century ago. That’s represented by a small blue bubble measuring 200 light-years in diameter surrounding the position of the Earth. For any alien civilizations to have heard us, they must be within the bubble.[…]

Continue reading at Popular Mechanics online…

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