Gazing Into the Past and Future at Historic Observatories

At the top of Mount Hamilton, near San Jose, Calif., Lick Observatory looks out over the dense sprawl of the San Francisco Bay Area. On a clear day from the 4,200-foot summit, you can see San Francisco to the north, as well as the entrance to Yosemite Valley, 120 miles east, as the crow flies. At night you can see even farther — millions of light-years into space.

When it was completed in 1888, Lick (named for its sponsor, James Lick) boasted the best telescopes and best year-round conditions of any observatory in the world. Its white domes were beacons for astronomers and visiting dignitaries, as well as hundreds of curious locals who made the long journey up the mountain each weekend.

Now, Lick Observatory is one of only a few remaining historic observatories still open to the public in the United States. Contemporary funding prioritizes ever-larger telescopes in dark, dry, high-altitude sites, like Chile’s Atacama Desert, or space-borne telescopes, such as the Hubble Space Telescope or the James Webb Space Telescope. Theirs are the extraordinary discoveries that regularly make the news. But historic observatories still have wonders to share with visitors and astronomers alike.

Lick Observatory and Lowell Observatory in Flagstaff, Ariz., which opened in 1894, both remain active in astronomical research. Other historic observatories now focus primarily on public outreach and education, including Yerkes Observatory (1897) in Williams Bay, Wis., and Mount Wilson Observatory (1904), outside Pasadena, Calif. At each of these sites, you can step into the history of the cosmos — experiencing the deep time of the stars, as well as more recent histories of discovery.

Looking through 19th-century glass at the Lick, you can see where E. E. Barnard spotted a new moon of Jupiter and James Keeler found a gap in Saturn’s rings. At Mount Wilson, Edwin Hubble, building on work done by Henrietta Swan Leavitt at Harvard, made an observation that proved there were other galaxies in the universe beyond the Milky Way. At Yerkes, you can peer through the 40-inch refracting telescope that surpassed Lick’s in size in 1897 and was used by a cadre of path-breaking women working in astronomy.

Yet, as the staff astronomer Elinor Gates told me, nothing compares to seeing these objects through the eyepiece of a telescope on the mountain. “You might look at a galaxy and it’s 25 million light-years away,” she said with visible enthusiasm. “It’s taken 25 million years for that light to get from that galaxy, come through the telescope to the eyepiece, to your eyeball. It’s a different experience than just looking at a pretty picture on a computer screen or in a book.” Here, she said, “You can actually start to experience the depth of time.”

Standing at the base of the Great Lick Refractor, I am stunned by its scale. Its tube reaches 57 feet toward the steep pitch of the dome, a 99-ton galvanized steel behemoth capable of rotating 360 degrees to accommodate the telescope’s opening. The walls are paneled with fragrant local redwood. Even the floor is exceptional — not only for its elegant circular parquet, but because the whole thing is an elevator, which once lifted astronomers up to the level of the eyepiece no matter where the telescope was pointed. And all of this material bounced and creaked up the mountain behind mules more than a century ago.

Flagstaff, home of Lowell Observatory, has been protecting the dark sky as a natural resource for more than half a century. Jeffrey Hall, Lowell’s executive director, told me that you can still see the Milky Way from downtown. The city’s first lighting ordinance, passed in 1958, prohibited the use of advertising searchlights. By the late 1980s, the ordinance was strengthened to require shielded outdoor lights that direct illumination downward, as well as “spectrum management,” which limits approved lighting to certain wavelengths.

Dr. Barentine suggested that light pollution is “the environmental challenge that we could definitively solve in our lifetimes.” And our success, he said, could benefit far more than just the field of astronomy. “We need a win as a species,” he said. “We need people to believe that we can take on significant problems and solve them.”

Those significant problems are all around us today. The charred skeletons of oak and manzanita sketch a haunting ring around Lick Observatory. In August of 2020, lightning ignited the drought-stricken hillsides. Residents were evacuated and several structures were lost, but fire crews managed to save the historic domes and equipment. When Aspen Mays and I visited this fall, smoke from wildfires burning along the California-Oregon border had drifted hundreds of miles south, drawing an acrid scrim over the Bay Area. As Aspen pointed out, when these observatories were built, their founders compiled years of meteorological research to confirm the sites’ future viability. No one expected the very climate to change.

At historic observatories we can see the enormous gains we’ve made in understanding our place in the universe, but they can also show us what we’ve lost — and what we will continue losing if we don’t do more now to limit our impact on the planet and the sky above it.

Lick Observatory, in Mount Hamilton, Calif., is usually open year-round. Weekend activities at the site include exhibits in the main observatory building, free timed talks in the dome of the 36-inch Great Refractor and a gift shop. The visitor’s gallery of the Shane 120-inch reflector telescope is open daily. View the observatory on Google Maps.

Lowell Observatory, in Flagstaff, Ariz., is open year-round. Ticketed activities on offer include stargazing, exhibits and science demos, scheduled science talks and opportunities to meet working astronomers. View the observatory on Google Maps.

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