Donald Machholz, comet hunter and co-inventor of Messier marathon, dies at age 69

Soft-spoken with an encyclopedic knowledge of the solar system’s small bodies, Machholz regularly scoured the heavens for most of his life.
By | Published: August 10, 2022 | Last updated on May 18, 2023
Donald Machholz is seen here using an 18-inch telescope at his observatory in Colfax, California.
Wikimedia Commons/Michele AnneLouise Machholz

Donald (Don) Machholz, an amateur astronomer who co-invented the Messier marathon and visually discovered 12 comets that now bear his name, died early yesterday morning (Aug. 9) at his home — called “Stargazer Ranch” — in Wikieup, Arizona. He was 69 years old.

Comet hunter

Born in 1952 in Portsmouth, Virginia, Machholz’s developed his interest in astronomy at the young age of 8. By age 13, he started exploring the sky with his first telescope: a modest 2-inch refractor.

Beginning Jan. 1, 1975, Machholz kicked off a personal comet hunting project. After more than three years and 1,700 hours at the eyepiece, he discovered his first comet on Sept. 12, 1978. His second find likewise took about 1,700 hours of searching. And over the next several decades, Machholz went on to visually discover 10 more comets that were later named after him.

In the years leading up to his death, Machholz was considered the most prolific visual comet discoverer alive. Over the course of his life, he spent a total of nearly 9,000 hours scanning the heavens for tail-toting cosmic relics visiting from the outer solar system.

Messier marathons and more

In addition to his unparalleled dedication to seeking out new comets, Machholz is also credited with co-inventing the Messier marathon in 1978. The Messier marathon is one-night race to observe all 109 objects compiled by French comet hunter Charles Messier during the late 18th century. And now, the marathon is a spring staple for amateur astronomers across the world. Over the course of four decades, Machholz completed 50 Messier marathons.

From 1978 until 2000, Machholz produced a monthly column called Comet Comments for the Association of Lunar and Planetary Observers. This popular column was then distributed to astronomy clubs and interested individuals across the world.

Machholz was also the author of several astronomy publications popular with amateur observers, including A Decade of Comets (1985), An Observer’s Guide to Comet Hale-Bopp (1996), and The Observing Guide to the Messier Marathon (2002).

Don may have finally completed the marathon of life, but his contributions to the world of astronomy will long live on.