Human World

Don Machholz, 1952-2022

Don Machholz: Bald man with white beard standing next to a large telescope.
Don Machholz visually discovered 12 comets that bear his name. He was one of the inventors of the Messier marathon, which amateur astronomers around the world use to test their skill. And he was a writer for EarthSky … and our friend. We will miss you, Don. Image via

The family has started a GoFundMe page. Visit it here

We are heartbroken to announce the passing of Don Machholz on August 9, 2022, at his home – Stargazer Ranch, Arizona – under one of the darkest skies in North America. Don was a friend and colleague at EarthSky. Indeed, he had a great love of the night sky and shared his boundless knowledge with our readers, using his characteristic wit. We send our condolences to his wife, Michele, and to his two sons.

Don Machholz: comet hunter

Don became interested in astronomy at age 8. With this in mind, he received his first telescope on October 7, 1965, a 2-inch (5-cm) refractor. Later, he received a 6-inch (15-cm) Criterion Dynascope and found all the Messier Objects in one year (1969-70). Consequently, he decided to attempt a comet hunting program, which he began on January 1, 1975. He found his first comet on September 12, 1978, after 1,700 hours of searching. Subsequently, his second find took an additional 1,742 hours. Eventually, he spent 8,900 hours comet hunting, during which he discovered a total of 12 comets which bear his name. He was, in fact, the number one living visual comet discoverer.

Messier Marathons, books and podcast

In 1978, Don was one of the independent inventors of the Messier Marathon, an attempt to find and view all 110 galaxies, clusters and nebulae in one night. In the last 40 years, he completed over 50 Messier Marathons and wrote two books on the subject. From 1978 through 2000, Don wrote a monthly column called “Comet Comments” for astronomy club newsletters and interested individuals worldwide. Between 1988 and 2000, Don was the Comets Recorder for the Association of Lunar and Planetary Observers. Don continued his visual comet hunting and Messier Marathons from Arizona, where he lived with his wife, Michele.

You can still find Don’s weekly podcast – Looking Up With Don – on most podcast platforms. His website is

Read Don’s articles at EarthSky.

All of us at EarthSky will miss you, Don. Rest in peace among the stars.

August 9, 2022
Human World

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