Lick Observatory’s damaged telescope dome still open to elements as another rainstorm approaches

After Santa delivered big trouble to Lick Observatory — the iconic astronomy complex atop Mount Hamilton east of San Jose where ferocious winds early Christmas morning blasted open the steel dome sheltering a historic telescope — crews are still scrambling to protect the instrument and sensitive equipment from rain.

The Great Refractor telescope, which was built in the 1880s, helped shape modern astronomy, and still draws thousands of visitors each year. It’s been wrapped in black tarps since gusts of wind blew a giant vertical door off the dome, and rain began pouring inside. The instrument, despite the soaking that occurred before it was covered, is believed undamaged.

But officials, observatory staff and contractor crews have been racing to come up with a plan to patch the opening, 4 to 8 feet wide, left by the missing door, to prevent more rain from hitting the telescope, or damaging electrical equipment and the laminated-wood floor inside the dome.

“We finalized our design idea for how to close up the slit this morning,” Lick Observatory site superintendent Jamey Eriksen said Friday afternoon. “It’s some custom woodwork to clamp onto a lip around the slit, and then we’re going to put plywood panels across, and then waterproof those plywood panels.”

Construction of the patch, involving a ladder-like wooden structure spanning the gap to hold the plywood, will start when the observatory gets a break in the weather, Eriksen said. He plans to have all necessary supplies on hand by the time that break comes, with work starting Monday or Tuesday if all goes well, he said. The contractor has said the job should take two or three days, Eriksen said.

The National Weather Service expects a storm to hit Mount Hamilton on Friday night and bring 2 to 2 1/2 inches of rain to the mountaintop by Tuesday morning, most of it falling by Sunday afternoon. A first band of moderate rain will probably come through after 10 p.m., with a second band following at around 4 a.m. Saturday, dropping moderate to heavy rain through Sunday afternoon, National Weather Service meteorologist Rachel Kennedy said Friday. Light rain was expected to continue afterward, increasing slightly Monday and Tuesday.

Winds on the mountain are predicted to be much less severe than over Christmas, when the strongest blasts hit 114 mph. Gusts around 50 mph are expected until early Saturday afternoon, when the winds should start subsiding, Kennedy said.

The gap in the dome necessitated another fix, to protect the sensitive electrical equipment that rotates the dome, opens and shuts the doors, operates the 58-foot-long telescope, and raises and lowers the broad, circular wood-laminate floor beneath it.

Using scaffolding, lumber, and plastic sheeting, workers have created a tent-like shroud suspended above the floor, that shunts rainwater to the sides, where it is being vacuumed up, Eriksen said.

Meanwhile, de-humidifying equipment has been added to an air intake, and about 20 industrial space-heaters are circulating the dried-out air beneath and above the wooden floor, which caught large amounts of rainfall after the dome door blew off.

Observatory staff have yet to inspect the Great Refractor, but are confident the tarps wrapping it are keeping the rain off the telescope, which holds lenses and electronics that could be damaged by water. Once the dome gap is patched, Eriksen said, “we’ll look for water being where it wasn’t supposed to be.”

Whether the 60-foot, crescent-shaped dome door, one of two that slid back to reveal the night sky, can be repaired and returned to its place will depend on a damage assessment, Eriksen said. “If that curvature is off and we can’t get it back, we couldn’t use it,” he said.

Observatory staff said earlier they believe old hardware in the dome may have made the door vulnerable to the gusts that blew it off.

Newer research telescopes at Lick appeared undamaged and will continue operating, according to the University of California, which owns and operates the observatory.

Built between 1880 and 1888, the Great Refractor with its lenses 3 feet across was for 100 years among astronomy’s premier research instruments. It gained global fame in 1892 after astronomers used it to discover Jupiter’s fifth moon, Amalthea, almost 300 years after Galileo found the planet’s first four.

Later advances in mirror-based telescopes eventually eclipsed the telescope’s scientific dominance, but it remains the centerpiece of the observatory’s programs for visitors, who can look through its eyepiece into deep space. Those programs are on hold indefinitely, with staff astronomer Elinor Gates calling the dome damage “a real blow” to the programs, with re-opening “many months” away.