The spinning black object at Vermillion River Observatory

The Vermilion River Observatory sat in a ravine near the Vermilion River, about 5 miles southeast of Danville, Illinois. It belonged to the University of Illinois. Its old 400 by 600 ft reflector had been sunk into the ravine itself, with a wooden trestle at its focus. By late December 1970 a new 120-ft steerable dish stood essentially complete. Locals had their own ideas about the place. Astronomer George McVittie recalled rumours that it was "this new way of listening to little green men on Mars."

Sunday, 9 May 1971. A man from Indiana drove to the observatory with binoculars. He wanted "to see a detailed view of the structure." He arrived a little before 10pm.

"As he investigated the antenna, he noticed an object in the sky that quickly approached from the southwest." He set down the binoculars. He picked up his Polaroid camera. "As he snapped a photo, the object silently moved nearer to the observatory in the quiet night."

Then it was overhead. The quiet eerily transformed into a loud humming noise. The object was larger than the antenna, and it spun like a top. No lights shone from its surface. He described it as "as black as the Ace of Spades" and "like burned metal." He fumbled the camera, trying for a second photograph. The object quickly disappeared into the night. He was left in shock and disbelief.

Project Blue Book had closed in 1969. After that, the Air Force told the public to take UFO reports to local universities and scientific institutions. Yet on 24 November 1971, six months after the sighting, Chanute Air Force Base in Rantoul, the nearest Air Force base, sent officers to interview the Indiana man. They came to view and borrow his photographs and to determine the legitimacy of his claims.

In June 1972, Chanute contacted him again and returned his records. He was thanked for his service. He was urged to consult his local scientific community for deeper examination and insight.

That same month, on 24 June 1972, a Champaign County citizen wrote to the Chanute commander asking about the base's involvement. Chanute replied that it "did receive the materials about the Vermillion River Observatory," but pointed the writer to local civil authorities. An information officer went further. "There was no investigation, and there is no report."

No official conclusion exists. No hoax claim and no conventional explanation have been published. Questions remain all the same. The object was black and unlit, seen after dark, and the account does not say how it stood out against the night sky. The interview came half a year after the event. The Polaroids were never published, and where they are now is unknown. In earlier local cases, Chanute officials had believed sightings were nothing more than light reflections on clouds. That was never said of this one.

The story survives in a single source. In December 2018, archives intern Thomas Kuipers wrote it up from the Chanute UFO correspondence file held by the Champaign County Historical Archives at the Urbana Free Library. One letter from that file has been digitised. The rest has never been published. An Air Force that borrowed a witness's photographs, then said there had been no investigation, remains the quiet puzzle at the heart of the case.