On the left of each sheet were 50 vertical columns of characters, one column for each channel monitored by the Big Ear’s receivers.
#Wow signal manual
As a result, a lot of manual effort went into searching through the data for interesting signals.Īnd so it was that in August of 1977, astronomer Jerry Ehman was poring through data from Big Ear’s survey of the sky, recorded on page after page of fanfold printer paper. Running on shoestring budgets, most of the early SETI programs devoted the bulk of their funding to telescope time, and little to data analysis. Most SETI programs were filler projects, designed to take advantage of downtime on radio telescopes between observations for more traditional studies. Source: North American Astrophysical Observatory.ĭespite capturing the popular imagination through the star-power of backers like Carl Sagan, SETI was not particularly well-funded. And so, in 1973, the Big Ear began its near-constant search for ET. The Ohio observatory, by virtue of its unique construction and its ability to do sky surveys, was identified early on by SETI scientists as the perfect tool for the job. But by the early 1970s, an interest in searching for potentially intelligent extraterrestrial civilizations by listening for specific radio signatures began to take hold of the radio astronomy community. The observatory was also used to study the Andromeda galaxy. It took the better part of a decade to build the Big Ear, and once it was switched on, its main goal was the completion of the Ohio Sky Survey for extragalactic radio sources. Source: North American Astrophysical Observatory. At the far end of the ground plane is the track holding the twin feed horns.
The steerable flat reflector is in the background, the fixed parabolic reflector is in the foreground. And even then, a great deal of “sweat equity” went into the construction of the Big Ear, with graduate students learning to weld specifically to build the telescope, and with critical equipment such as the parametric amplifiers needed for the receiver being built at cost by an OSU alumnus. His original design called for 600-meter-wide reflectors, but when the National Science Foundation grant came through in 1955 at a paltry $48,000, the design was reduced to what was possible. Kraus had actually designed a much, much bigger antenna. The Big Ear was big: the flat reflector alone was 33 meters tall and 100 meters wide, and the ground plane stretched 150 meters between the two reflectors. Although in general the telescope was static and pointed wherever the Earth’s rotation took it, the feedhorn tracking coupled with adjustments to the tilt of the flat reflector gave some control to which part of the sky was being surveyed. At the focal point of the paraboloid reflector was a small shack containing the feed horns, which could move across the width of the telescope on railroad tracks. Between these two elements lay a large, flat ground plane area of aluminum-covered pavement. It consisted of a large, flat reflector section of steel mesh standing across an open space from a wide, stationary paraboloid reflector. The design of the telescope would be extremely simple, especially compared to the more typical fully steerable dish antenna. Kraus first described his idea for a telescope capable of detecting extraterrestrial radio signals in an article for Scientific American in 1955. Kraus was no stranger to big science - during WWII he developed methods for degaussing naval ships to protect them from magnetically detonated mines, and he worked on a massive cyclotron for the University of Michigan.ĭr. Affectionately known as “The Big Ear”, the Ohio State University Radio Observatory was the vision of John D. Understanding the Wow! Signal requires a look at the instrument that produced it.
If it was sent from a region of space with habitable planets, it’s at least worth a listen. How we came to hear this signal, what it could possibly mean, and where it might have come from are all interesting details of an event that left a mystery in its wake, one that citizen scientists are now looking into with a fresh perspective. When the data was analyzed later, an astronomer’s marginal exclamation of the extraordinarily powerful but vanishingly brief blip would give the signal its forever name: the Wow! Signal. Shortly after 10:00 PM, the Earth’s rotation slewed the telescope through a powerful radio signal whose passage was noted only by the slight change in tone in the song sung every twelve seconds by the line printer recording that evening’s data. On a balmy August evening in 1977, an enormous radio telescope in a field in the middle of Ohio sat silently listening to the radio universe.
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