Mysteriously shuttered solar observatory set to reopen, although some questions remain

The entrance to Sunspot Observatory is blocked near Alamogordo, New Mexico. Photo / AP

The organisation in charge of the New Mexico solar observatory that was mysteriously evacuated and shuttered for more than a week attributed the closure to a threat posed by a suspect in a criminal investigation and said the facility will reopen on Monday (US time).

In a statement on Sunday, the Association of Universities for Research in Astronomy said employees will return to work after "recent developments in the investigation" convinced officials that there was no risk to the staff.

The association also for the first time provided some details about why the observatory had to be closed, saying in a statement that officials had been cooperating with an inquiry of criminal activity in the area and "became concerned that a suspect in the investigation potentially posed a threat to the safety of local staff and residents."

The sudden evacuation of the National Solar Observatory in Sunspot, New Mexico, on September 6 had spawned online speculation, fuelled by authorities' reluctance to provide any information about why the facility was closed.

The local sheriff and those tasked with guarding the observatory after the closure said that even they had been kept in the dark. FBI agents - who were on the scene during the evacuation - declined to say anything. Internet sleuths wondered whether researchers had spotted something extraterrestrial, or whether the solar telescope at the site had possibly been hacked to spy on a nearby missile testing range.

Roswell, New Mexico - where the 1947 crash of a flying object sparked so much interest that the city is now home to a UFO museum - is only about a 2 1/2-hour drive from the observatory.

The association's statement did not offer details about the nature of the criminal investigation, the suspect or the developments that led officials to conclude that there was no longer a risk. The association said it was working with a security service, in part because it expected more visitors in light of the mysterious closure. The site is normally open to the public.

"We recognize that the lack of communications while the facility was vacated was concerning and frustrating for some," the association said. "However, our desire to provide additional information had to be balanced against the risk that, if spread at the time, the news would alert the suspect and impede the law enforcement investigation. That was a risk we could not take."

FBI spokespeople in New Mexico and Washington and a spokeswoman for the association did not return messages seeking comment Sunday night. Otero County Sheriff Benny House said Sunday evening that he had not been told why the facility was closed, and was not aware of an investigation in the area or a person who might pose a threat.

"I know absolutely nothing about what they're talking about. They have not talked to us," House said. "If there's a threat, I think I should know. I'm pretty disappointed."

The National Solar Observatory sits at more than 9,000 feet in the Lincoln National Forest in the southern part of New Mexico, and it is part of a larger astronomy facility on the site. The association's statement said the closure was based in part on "logistical challenges associated with protecting personnel at such a remote location." The adjacent Apache Point Observatory, a collection of telescopes about half a mile away, continued to operate as normal, though, even as the Sunspot facility remained closed.