WASHINGTON — The upcoming anniversary of an iconic radio telescope could be tarnished by the ongoing shutdown of the U.S. federal government, as the observatory plans to furlough essentially all of its employees and stop observations by the middle of October.

Operations of the Arecibo Observatory in Puerto Rico are continuing for the moment despite the shutdown, observatory director Robert Kerr said at an Oct. 2 press conference in Washington. He said the National Science Foundation, Arecibo’s principal funder, authorized the observatory to spend what remaining funds it has on hand, although because the shutdown occurred at the beginning of the new fiscal year there are few such funds available.

“In essence, we are currently operating at risk,” Kerr said. “We think we could do that for maybe a couple of weeks, and then there may be some profound impacts.”

Those impacts are likely to come in the form of personnel furloughs, since 80 percent of the observatory’s operating budget is labor. Kerr said the observatory had not made specific plans for who would be furloughed, but it would likely involve effectively all of its approximately 125 employees. “I would hope it would be an equitable distribution, which would probably be everybody,” he said.

Arecibo Observatory, formally known as the National Astronomy and Ionosphere Center, started operations Nov. 1, 1963. The press conference was intended to highlight the observatory’s upcoming 50th anniversary, including a scientific symposium and public events at the observatory in late October. Observatory officials did not indicate if those events would be postponed if the shutdown continues.