From Cold War radar to cosmic truths

Forty-five kilometers northwest of Boston sits a giant white sphere, a structure that looks like a misplaced golf ball than a tool for astronomy. This is the Haystack Observatory, a multidisciplinary radio science center owned by MIT. Its story begins in the heat of the Cold War. Construction started in 1960 by MIT's Lincoln Laboratory for the U.S. Air Force, which needed advanced radar systems to track objects in orbit. The facility, originally named the Haystack Microwave Research Facility, became operational in 1964. Its primary instrument, a 37-meter (121-foot) steerable antenna, was initially conceived for space tracking and communication. This powerful radar could resolve objects down to 25 cm and track satellites in geostationary orbit.

The main antenna is protected by a 46-meter (151-foot) diameter radome, the largest of its kind in the world. This enclosure, made of 932 triangular fabric panels, allows the telescope to operate in nearly all weather conditions and protects the sensitive instrument from the elements. In 1970, the facility was transferred from the Air Force to a consortium of universities led by MIT called the Northeast Radio Observatory Corporation (NEROC), shifting its focus toward fundamental astronomical research. The radar, now called the Haystack Ultrawideband Satellite Imaging Radar (HUSIR), still contributes data to the United States Space Surveillance Network, but the majority of its time is dedicated to science.

Creating a planet-sized instrument

Haystack Observatory is a part of one of modern astronomy's most ambitious projects: the Event Horizon Telescope (EHT). The EHT is not a single instrument, but a global network of radio telescopes that work together using a technique called Very Long Baseline Interferometry (VLBI). By precisely timing and combining the radio signals collected at dishes spread across the planet—from the South Pole to Spain to Hawaii—the EHT creates a virtual telescope with a diameter nearly the size of Earth. This extraordinary angular resolution is what allows astronomers to see the immediate environment of supermassive black holes.

Haystack processes the data. Petabytes of data from each participating telescope are recorded onto hard drives and physically shipped to two central processing hubs: one at the Max Planck Institute for Radio Astronomy in Germany, and the other at Haystack. Here, a supercomputing cluster of about 800 CPUs correlates and combining the disparate data streams to synthesize a single, coherent image. This process helped create the first-ever image of a black hole, the supermassive object at the center of galaxy M87, released in 2019, and later, the image of Sagittarius A*, the black hole at the center of our own Milky Way galaxy. Beyond black holes, Haystack's telescopes also perform research in geodesy—the science of measuring Earth's shape and rotation—and atmospheric studies, probing the ionosphere.

Practical Information

Opening Hours

The grounds are open to the public on weekdays. The observatory holds public open houses twice a year, typically on the third Thursday of May and October, which require advance registration for free tickets.

Admission

Free.

Accessibility

The observatory is located on a hill. Main buildings are accessible. The grounds include paved roads and some unpaved trails.

Website

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An Earth-Sized Telescope to See Black Holes

From Cold War radar to cosmic truths

Creating a planet-sized instrument

💡Fun Facts

References

There's more in the app

Practical Information

An Earth-Sized Telescope to See Black Holes

From Cold War radar to cosmic truths

Creating a planet-sized instrument

💡Fun Facts

References

There's more in the app

Practical Information

Nearby curiosities

Nearby curiosities