Donald Machholz

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Donald Machholz

Donald Machholz

Donald Edward Machholz, born October 7, 1952 in Portsmouth, Virginia, is an American amateur astronomer and science writer who is the most successful living visual comet discoverer in history. Credited with the discovery of 12 comets, that include the periodic comets 96P/Machholz141P/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 most recently C/2018 V1 (Machholz-Fujikawa-Iwamoto) [1][2] 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.[3] Amateur astronomer Machholz utilizes a variety of methods in his comet discoveries, in 1986 using 29×130 binoculars he discovered 96P/Machholz.[4]

Machholz is considered to be one of the inventors of the Messier marathon, which is a race to observe all the Messier objects in a single night.

Awards and Honors

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)


  • 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

Personal life

In 2014 he married photographer and astronomer, Michele Machholz and they reside at 4600 feet outside Wikieup, Arizona.


  1. ^ Gus Thomson (March 30, 2010). “Patience leads to new comet discovery by Colfax amateur astronomer”. Auburn Journal. Retrieved March 30, 2010.
  2. ^ Roger W. Sinnott (March 27, 2010). “New Comet Machholz”Sky & Telescope. Retrieved March 30, 2010.
  3. ^ Associated Press (June 16, 1985). “Amateur Astronomer Nails Down His Second Comet”Los Angeles Times. Retrieved December 29, 2016.
  4. ^ Alan MacRobert (December 2, 2008). “A Very Oddball Comet”. Sky & Telescope. Retrieved December 2, 2008.

5. Gareth V. Williams (November 11, 2018) “MPEC 2018-V151: COMET C/2018 V1 (Machholz-Fujikawa-Iwamoto)” Minor Planet Center.

6. Bob King (November 9, 2018) “Amateur Don Machholz Discovers His 12th Comet!” Sky & Telescope.