THE STAR ATTRACTION

BY: NOAH AUSTIN

LOWELL OBSERVATORY SITS on Mars Hill overlooking Flagstaff, and it's home to a 24-inch Alvan Clark refracting telescope. The age of the "Clark," as it's known, is best expressed not in years but with an observation by Lowell mechanical engineer Ralph Nye: "The guy who made these parts rode a horse to work." The Clark's history includes aiding in the discovery of Pluto and mapping the surface of the moon. In recent years, it's mostly been used by the observatory's visitors, who line up outside its wooden dome on clear evenings for views of Jupiter, Saturn and other gems of the night sky. But more than a century of use caught up with the Clark, and in 2014, Lowell embarked on an unprecedented, massive restoration of the telescope and its dome. The instrument was disassembled; decades of grease, dust and paint were stripped away; and broken parts were replaced with exact modern replicas. And Nye gained a new appreciation for those who created this precise, sophisticated machine. "After taking this apart, you respect the people who put it together in the first place," he says. "They didn't think about time or money - just about how they were going to do it."

A sign in Lowell's driveway has long proclaimed the observatory the "Home of Pluto." The sign keeps getting stolen, but maybe that's appropriate given that Pluto recently lost its status as one of our solar system's planets. It's now classified as a "dwarf planet," which could have spurred hard feelings around the observatory where Pluto was discovered in 1930. But Lowell historian Kevin Schindler says visitors seem most concerned about Pluto's plight. "We still have people coming in asking, 'Are you guys OK?'" he says. "But it's a great way of introducing people to how science works." He points out that in the early 1900s, asteroids were called planets until a new classification was created. The same thing happened with Pluto; it just took longer. It's a common misconception that the Clark was used to discover Pluto. Clyde Tombaugh actually first spotted it using photographic plates from a different telescope at the observatory. He then used the images as a guide in locating the new object with the Clark. Percival Lowell set up his observatory long before that, in 1894. Two years later, the Clark arrived. It was tested in a dome designed for a much smaller telescope - creating such a tight fit that it stuck out the dome's doors in certain positions. A new, 40-foot dome, created from local ponderosa pines, was built in Flagstaff but first assembled in Mexico, whereLowell

took the Clark in late 1896 to make observations of Mars during Flagstaff's winter. Both the dome and the telescope returned to Flagstaff in 1897 and have been there since.

The dome originally rotated on iron wheels, which worked poorly. Lowell engineers then tried floating the dome in a trough of salt water, which wouldn't freeze like fresh water would. But the trough leaked constantly, so the old wheels returned, this time with a metal track. Finally, in the 1960s, the observatory installed the 24 truck tires on which the dome rotates today.

Around that time, the Aeronautical Chart and Information Center, a branch of the Air Force, began using the Clark to map the lunar surface for NASA's Apollo missions. Since the end of that project in 1969, the Clark has primarily been used for public viewing. Lowell Putnam, the observatory's sole trustee and Percival Lowell's great-grandnephew, says that's put more stress on the telescope than scientific work would.

"An astronomer fixes on one point and sort of stays there," Putnam says. "For the public, we're moving it around and working it much harder. The fact that the telescope was still functional 120 years [after installation] is a testament to the workmanship."

But the Clark wasn't without problems. The biggest stemmed from its 18-inch support wheel, which was used instead of bearings because of the 7-ton telescope's size. Over the years, imperfections in the wheel took their toll. At one point, Nye says, rotating the Clark by hand produced a loud boom that caused the entire telescope to shake. Nye used a stethoscope to look for the source of the problem, but he couldn't find it without taking the whole thing apart.

Eventually, a piece broke off and the noise stopped. Later, Nye got a copy of a patent for a similar telescope in Colorado, enabling him to figure out what was wrong. "If I would have had that first, I would have maybe picked that up a little sooner," he says.

"Peter, Jeff and I are all perfectionists, and we're obsessive-compulsive about what we do," Nye says. That's a necessity in astronomy, where a hundredth of an inch can mean the difference between a clear view and a blurry one.

A few years ago, Nye says, Lowell "got a hold of a really good fundraiser, and I jokingly said, 'We ought to get some money to fix up the Clark." The fundraiser and Schindler sprang into action, publicizing the observatory's "Restore the Clark" camCampaign on the Internet and social media. "Suddenly," Nye says, "we had all this money to do it."

In August 2014, the Clark's dome is empty, and Nye and a carpenter are repairing its wooden parts, replacing shutter ropes and tightening nails that have started to come loose. The 1954 truck tires line the base of the dome's interior, and Nye says one or two get replaced each year. But the tires "are a little hard to get now, because some guy bought all the old molds," he says, and using a different tire size would mean replacing all the axles.

That's the nature of restoring a 118-year-old building and telescope: Solve one problem, and another problem will surface. But Lowell's staff is up to the task. When they found, for example, that they didn't have the right tool to remove the four ancient bolts securing the Clark to its pedestal, they simply had two wrenches made one to loosen the bolts and one to tighten them.

The Lowell machine shop, up the hill, is where the pieces of the Clark now sit. The larger, heavier components had to be removed through the dome's roof using a 50-foot crane, then trucked to the machine shop on trailers. There, Nye and his team, including machinists Jeff Gehring and Peter Rosenthal, have refurbished existing parts and created replacements for broken ones. They've also removed the telescope's paint, which was added with a brush and, in Nye's view, "looked like heck."

Nye points out a setting circle, used to find objects in the sky by their celestial coordinates. It's worked well enough, but its numbers and lines were painted on by hand in the 1890s. Today's Lowell engineers have made it more precise. Rosenthal created new knobs for the back of the telescope, then painted them five times until he was satisfied.

Many of the Clark's components are made of brass, but at some point, they were covered with dark paint. “Every piece of brass on this telescope is a piece of jewelry to us, so why paint it?” Nye says. They got a special paint stripper to remove the lead-based paint, then added an organic powder to neutralize the lead so they could dispose of it. Other parts got a baked-on powder coating.

CLOCKWISE FROM TOP LEFT: Old and new collide as Lowell engineers use light from an iPhone to make precise adjustments to the ancient telescope. The restoration process involved stripping away layers of paint and polishing the instrument's metal parts. Lowell machinist Peter Rosenthal (left) and Nye examine the Clark's lens before reattaching it to the telescope's tube. Rosenthal displays a dial to be installed at the observing end of the telescope. It's one of several brass parts that were restored to their original shine.

At this point, the Clark is almost ready to reassemble. Even in its discombobulated state, it's a far cry from the “mess of grease and dust and dirt” it was before, Nye says. “It'll be like a brand-new telescope.” Seven months later, on a cold morning in mid-March, Nye and his crew have just finished putting the bulk of the Clark back into its dome. A crane lowered the telescope's “tube” through the dome's open shutters. The Clark's priceless main lens has also been reinstalled, which Nye says “takes a lot of worry off.” Though the heavy lifting is done, there's still plenty to do before the Clark can reopen to the public, which Nye anticianticipates will happen this summer. The team must install 80 feet of control rods and some other accessories. The massive telescope must be precisely balanced; after that's done, it'll take only a fingertip to move it. And Nye will climb inside the tube to make adjustments — a prospect that would make even the mildest claustrophobe sweat.

Perhaps most importantly, though, Nye and others at Lowell will have to relearn how to use the refurbished and upgraded instrument. That will enable them to develop a user manual for operators, who can then familiarize themselves with the Clark just as Percival Lowell did more than a century ago. Nye says that will allow the telescope to keep wowing observatory visi-

Visitors for “another hundred years.”

“We spent almost $300,000 on this rebuild,” he says, “and this is a priceless antique. It deserves to be operated by people

who really know how to use it.”

To learn more about Lowell Observatory, and to check on the status of the Clark Telescope, call 928-774-3358 or visit www.lowell.edu.