NEW YORK, NY.- A total solar eclipse may be one of the most profoundly visceral experiences you can have without ingesting anything illegal.

Eight times, I’ve been through this cycle, feeling the light melt and seeing the sun’s corona spread its pale feathery wings across the sky. As you read this article, I will be getting ready to go to Dallas, along with family and old friends, to see my ninth eclipse.

One old friend won’t be there: Jay M. Pasachoff, who was a longtime astronomy professor at Williams College. I’ve stood in the shadow of the moon with him three times: on the island of Java in Indonesia, in Oregon and on a tiny island off Turkey.

I was looking forward to seeing him again next week. But Jay died in late 2022, ending a long career as the pushy cosmic evangelist.

“We are umbraphiles,” Pasachoff wrote in The New York Times in 2010. “Having once stood in the umbra, the Moon’s shadow, during a solar eclipse, we are driven to do so again and again, whenever the Moon moves between the Earth and the Sun.”

As an eclipse came around, Jay could be found wearing his lucky orange pants and heading expeditions of colleagues, students (many of whom became professional astronomers and eclipse chasers themselves), tourists and friends to corners of every continent.

“Jay is probably responsible for inspiring more undergrads to go on to careers in astronomy than anyone else ever,” said Stuart Vogel, a retired radio astronomer at the University of Maryland.

His death ended a remarkable streak of success in pursuing the darkness. He saw 75 eclipses, 36 of which were total. In all, according to the Eclipse Chaser Log, Pasachoff spent over one hour, 28 minutes and 36 seconds (he was a stickler for details) in the shadow of the moon.

“He was larger than life,” said Scott McIntosh, deputy director of the National Center for Atmospheric Research, who said that one of Pasachoff’s eclipse expedition hats was hanging on the wall of his office in Boulder, Colorado.

As the world prepares for the last total eclipse to touch the lower 48 states in the next 20 years, it seems strange not to have him on the scene.

“He was probably the single most influential figure in my professional life, and I feel his absence acutely,” said Dan Seaton, a solar physicist at the Southwest Research Institute in Boulder.

Pasachoff was a 16-year-old freshman at Harvard University in 1959 when he saw his first eclipse, off the shore of New England in a DC-3 chartered by his mentor, Harvard professor Donald Menzel. He was hooked.

After a doctorate from Harvard, Pasachoff eventually joined Williams College in 1972 and immediately began recruiting eclipse chasers.

Daniel Stinebring, now an emeritus professor at Oberlin College, was a freshman when he was recruited for an eclipse expedition on the shore of Prince Edward Island.

The eclipse day dawned cloudy. Pasachoff, channeling his old mentor, Menzel, hired a pilot and a small plane. He sent his young student to the airport with a fancy Nikon camera and told him to photograph the eclipse while hanging out of an open airplane door.

A year later in 1973, the young Stinebring found himself on the shores of Lake Turkana in Kenya with Pasachoff and teams from 14 other universities waiting for the longest eclipse of the century, some seven minutes of totality. The moment was life-altering, he said.

Pasachoff, his old students said, went out of his way to inform the local people, not to be afraid of the eclipse and how to watch it safely.

Pasachoff prided himself on his preparation.

“Jay always had a Plan B,” said Dennis di Cicco, a longtime editor at the magazine Sky & Telescope.

In 1983, Pasachoff arrived in Indonesia for an eclipse expedition sponsored by the National Science Foundation. He discovered that the digital tape recorder on which all his data would be stored was broken.

Pasachoff called his wife, Naomi, a science historian also at Williams College who was back home in Massachusetts. She tried to order a new tape recorder only to be told that the official paperwork needed to ship the device to Java would take several days. Di Cicco was pressed into service. Within 24 hours, he had renewed his passport, picked up the tape recorder and boarded a flight to Indonesia. Di Cicco arrived just one day before the eclipse.

Pasachoff paid for the $4,000 round-trip ticket.

Solar eclipses are now big business and less in need of an evangelist, said Kevin Reardon, a Williams alumnus and now a scientist with the National Solar Observatory and the University of Colorado in Boulder, in an interview. “Now, everyone knows eclipses are great.”

Pasachoff prided himself on hardly ever missing an eclipse, and he credited luck with the weather for having never been clouded out. He always managed to secure the best sites, and Mazatlán in Mexico seemed most promising for 2024.

But he sent me an email in 2021 saying that a lung cancer had spread to his brain, and he offered material for an obituary.

Still, he wrote, “I have not given up the idea of going to the Dec. 4 Antarctic eclipse, for which I have three research lines.” He did go and sent back eerie photos of the ghost sun over an icy horizon, his last excursion into the darkness. Even so, he kept planning for the next eclipses.

“You know, there’s an eclipse, and then the next one, and then the next,” Reardon said. “He wanted to see every eclipse and did not want to think that there will be a last one.”

It will be lonely in the shadows on Monday.

This article originally appeared in The New York Times.