# Donald Machholz

Donald Edward Machholz (October 7, 1952 – August 9, 2022) was an American amateur astronomer who was credited with the discovery of 12 comets that bear his name.

## Personal life and death

In 2014, he married photojournalist Michele Machholz. They resided at the Stargazer Ranch in Wikieup, Arizona.
Machholz died in the early morning of August 9, 2022, at his home in Wikieup, Arizona, from complications of COVID-19. His obituary at Astronomy stated, "In the years leading up to his death, Machholz was considered the most prolific visual comet discoverer alive."

## Career

He spent more than 9,000 hours comet hunting in a career spanning over 50 years. These comets include the periodic comets 96P/Machholz, 141P/Machholz, the non-periodic C/2004 Q2 (Machholz) that were visible with binoculars in the northern sky in 2004 and 2005, C/2010 F4 (Machholz), and C/2018 V1 (Machholz-Fujikawa-Iwamoto) In 1985, comet Machholz 1985-e, was discovered using a homemade cardboard telescope with a wide aperture, 10 inches across, that gave it a broader field of view than most commercial telescopes. Machholz utilized a variety of methods in his comet discoveries, in 1986 using 29×130 binoculars he discovered 96P/Machholz.
Machholz was one of the inventors of the Messier Marathon, which is a race to observe all the Messier objects in a single night.
Asteroid 245983 Machholz, discovered by Kazimieras Černis, was named in honor of Machholz in November 2017.

### Comets discovered

* 1978 Comet Machholz (1978l)
* 1985 Comet Machholz (1985e)
* 1986 Comet 96P/Machholz
* 1988 Comet Machholz (1988j)
* 1992 Comet Tanaka-Machholz (1992d)
* 1992 Comet Machholz (1992k)
* 1994 Comet Nakamura-Nishimura-Machholz (1994m)
* 1994 Comet 141P/Machholz 2
* 1994 Comet Machholz 1994r
* 2004 Comet Machholz (C/2004 Q2)
* 2010 Comet Machholz C/2010 F4
* 2018 C/2018 V1 (Machholz-Fujikawa-Iwamoto)

## Awards and honors

* 1978 Tuthill Comet Award Roger Tuthill for discovering Comet Machholz (1978L)
* 1985 Tuthill Comet Award Roger Tuthill for discovering Comet Machholz (1986e)
* 1986 Tuthill Comet Award Roger Tuthill for discovering Periodic Comet Machholz 1 (1986e)
* 1994 Walter H. Haas Award Association of Lunar and Planetary Observers
* 1995 Machholz was the recipient of the G. Bruce Blair Medal
* 2000 Peggy Haas Service Award Association of Lunar and Planetary Observers Service to Association of Lunar and Planetary Observers
* 2005 Edgar Wilson Award Harvard's Smithsonian Astrophysical Observatory for discovering Comet Machholz C/2004 Q2
* 2010 Edgar Wilson Award Harvard's Smithsonian Astrophysical Observatory for discovering Comet Machholz C/2010 F4
* 2017 Asteroid 245983 Machholz discovered by Kazimieras Černis was named in honor of Donald Machholz in November 2017
* 2018 Edgar Wilson Award Harvard's Smithsonian Astrophysical Observatory for discovering Comet C/2018 V1 Machholz-Fujikawa-Iwamoto
* 2021 Leslie C. Peltier Award Astronomical League for the visual discovery of 12 comets and contributions to astronomy

## Books

* The Observing Guide to the Messier Marathon: A Handbook and Atlas
* Decade of Comets: A Study of the 33 Comets Discovered by Amateur Astronomers Between 1975 and 1984
* An observer's guide to comet Hale-Bopp: Making the most of Comet Hale-Bopp: when and where to observe Comet Hale-Bopp and what to look for