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Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965.[2][3] In 2011, the Observatory was named one of "The World's 100 Most Important Places" by TIME. It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh.

Lowell Observatory
Clark dome.jpg
The Clark Telescope Dome on Mars Hill
OrganizationPrivate institution
Observatory code690 Edit this on Wikidata
LocationFlagstaff, Arizona
Coordinates35°12′10″N 111°39′52″W / 35.20278°N 111.66444°W / 35.20278; -111.66444Coordinates: 35°12′10″N 111°39′52″W / 35.20278°N 111.66444°W / 35.20278; -111.66444
Altitude2,210 m (7,250 ft)
Discovery Channel Telescope4.28 m (169 in) telescope (located at Happy Jack, Arizona)
Perkins Telescope180 cm (72 in) cassegrain telescope (located at Anderson Mesa)
John S. Hall Telescope110 cm (42 in) Ritchey-Chretien telescope (located at Anderson Mesa)
Unnamed telescope79 cm (31 in) reflecting telescope (located at Anderson Mesa)
LONEOS Schmidt Telescope64 cm (25 in) catadioptric (located at Anderson Mesa)
24-inch Clark Telescope61 cm (24 in) Alvan Clark refractor
Unnamed telescope53 cm (21 in) reflecting telescope
Unnamed telescope46 cm (18 in) astrograph
John Vickers McAllister Telescope41 cm (16 in) Boller and Chivens cassegrain telescope
Abbot L. Lowell Astrograph (Pluto Discovery Telescope)33 cm (13 in) astrograph
Planet Search Survey Telescope(located at Anderson Mesa)
Navy Precision Optical Interferometersix-aperture astronomical interferometer with baselines up to 437 m (1,434 ft) (located at Anderson Mesa, operated in partnership with the USNO (through NOFS) and the NRL)
Lowell Observatory
The Slipher Rotunda Museum at Lowell Observatory
Lowell Observatory is located in Arizona
Lowell Observatory
Lowell Observatory is located in the United States
Lowell Observatory
MPSFlagstaff MRA (AD)
NRHP reference #66000172
Significant dates
Added to NRHPOctober 15, 1966[1]
Designated NHLDecember 21, 1965[2]
Lowell Observatory is located in the United States
Lowell Observatory
Location of Lowell Observatory
Commons page Related media on Wikimedia Commons

The observatory was founded by astronomer Percival Lowell of Boston's Lowell family and is overseen by a sole trustee, a position historically handed down through the family. The first trustee was Lowell's third cousin Guy Lowell (1916–1927). Percival's nephew Roger Putnam served from 1927 to 1967, followed by Roger's son Michael (1967–1987), Michael's brother William Lowell Putnam III (1987–2013), and current trustee W. Lowell Putnam.

Multiple astronauts attended the Lowell Observatory while the moon was being mapped for the Apollo Program. The training was in session in 1963.[4]

The observatory operates several telescopes at three locations in the Flagstaff area. The main facility, located on Mars Hill just west of downtown Flagstaff, houses the original 61-centimeter (24-inch) Clark Refracting Telescope, which is now used for public education, with 85,000 annual visitors. The telescope, built in 1896 for $20,000, was assembled in Boston by Alvan Clark & Sons and then shipped by train to Flagstaff. Also located on the Mars Hill campus is the 33-centimeter (13-inch) Pluto Discovery Telescope, used by Clyde Tombaugh in 1930 to discover the dwarf planet Pluto.

In 2014, the 8,000 square foot Observatory was opened. This observatory included many rooms with tools that were useful to observers including a library for research, a room for processing, photographic glass plates, multiple antique instruments used by previous astronomers, and many artifacts. The observatory does contain areas that are closed to the public view, although there are multiple places that tourists are welcome to visit. [5]

Lowell Observatory currently operates four research telescopes at its Anderson Mesa dark-sky site, located 20 km (12 mi) southeast of Flagstaff, including the 180-centimeter (72-inch) Perkins Telescope (in partnership with Boston University) and the 110-centimeter (42-inch) John S. Hall Telescope. Lowell is a partner with the United States Naval Observatory and Naval Research Laboratory in the Navy Precision Optical Interferometer (NPOI) also located at that site. The Observatory also operates smaller research telescopes at its historic site on Mars Hill and in Australia and Chile.

Past Anderson Mesa, on the peak of Happy Jack, Lowell Observatory has also built and is commissioning the 4.28-meter (169-inch) Discovery Channel Telescope in partnership with Discovery Communications, Inc.



The observatory has carried out a wide array of research. One of its programs was the measurement of the variability of solar irradiance.[6] When Harold L. Johnson took over as the director in 1952, the stated objective became to focus on light from the Sun reflecting from Uranus and Neptune.[6] In 1953, the current 53 cm (21-inch) telescope was erected.[6] Beginning in 1954, this telescope began monitoring the brightness of these two planets, and comparing these measurements with a reference set of Sun-like stars.[6]

Beginning in 2012, Lowell Observatory began offering camps for children known as LOCKs (Lowell Observatory Camps for Kids). The first camp was established for elementary students. Later on, in 2013, they added an additional camp program for preschool children. The following year they added another program for middle school students. (“Kelly”, Manager at Lowell Observatory). Kids have the opportunity to learn hands-on about science, technology, engineering, and math (STEM) through a variety of activities that include games, experiments, story time, art, music, and more.

In 2016, Kevin Schindler published Lowell Observatory, a 128 page book containing over 200 captions and pictures. Arcadia Publishing’s Images of America included it in their series, which increased the enthusiasm of space to the public. The book itself features the popular reputation of Lowell Observatory, encompassing the revolutionary research of scientists and how they contributed to the field of astronomy [7] [8].

Discovery Channel Telescope (DCT)Edit

Rotunda building

Lowell Observatory is building a major new reflecting telescope in partnership with Discovery Communications, located near Happy Jack, Arizona. This Discovery Channel Telescope (DCT), located within the Mogollon Rim Ranger District of the Coconino National Forest, is expected to be the fifth-largest telescope in the contiguous United States, and it will enable the astronomers of Lowell Observatory to enter new research areas deeper into outer space.

The DCT and the research carried out there will be the focus of ongoing informative and educational television programs about astronomy, the sciences, and technology to be telecast on the Discovery channels. The primary mirror of the Discovery Channel Telescope will be 4.28 m (169 in) in diameter, with an uncommon meniscus design for such a large mirror. This mirror was ground and polished into its parabolic shape at the Optical Fabrication and Engineering Facility of the College of Optical Sciences of the University of Arizona (in Tucson, Arizona).

Current researchEdit

Lowell Observatory's astronomers conduct research on a wide range of solar system and astrophysical topics using ground-based, airborne, and space-based telescopes. Among the many current programs are a search for near-Earth asteroids, a survey of the Kuiper Belt beyond Neptune, a search for extrasolar planets, a decades-long study of the brightness stability of the sun, and a variety of investigations of star formation and other processes in distant galaxies. In addition, the Observatory staff designs and builds custom instrumentation for use on Lowell's telescopes and elsewhere. For example, Lowell staff built a sophisticated high-speed camera for use on the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is a joint project of the United States and German space agencies and consists of a 2.5-meter (8.2-foot) telescope on board a Boeing 747 SP.


See alsoEdit


  1. ^ "National Register Information System". National Register of Historic Places. National Park Service. January 23, 2007.
  2. ^ a b "Lowell Observatory". National Historic Landmark summary listing. National Park Service. Retrieved September 27, 2007.
  3. ^ Marilynn Larew (October 31, 1977). "National Register of Historic Places Inventory-Nomination: Lowell Observatory" (PDF). National Park Service. Retrieved May 5, 2009. and Accompanying six photos, exterior, from 1964 and 1976
  4. ^ "History". Lowell Observatory. Retrieved April 1, 2019.
  5. ^ "History". Lowell Observatory. Retrieved April 1, 2019.
  6. ^ a b c d Wotkyns, Steele (2006). "Lowell Observatory's 21-inch Telescope Delivering Long-Term Results". Reflector. the Astronomical League. LVIII (2): 16.
  7. ^ "History". Lowell Observatory. Retrieved April 3, 2019.
  8. ^ "Lowell Observatory". Retrieved April 3, 2019.
  9. ^ Schleicher, David G.; Millis, Robert L.; Thompson, Don T.; Birch, Peter V.; Martin, Ralph; et al. (1990). "Periodic variations in the activity of Comet P/Halley during the 1985/1986 apparition". Astronomical Journal. 100: 896–912. Bibcode:1990AJ....100..896S. doi:10.1086/115570.


  • Strauss D. (1994). "Lowell, Percival, Pickering, W.H. and the founding of the Lowell Observatory". Annals of Science. 51 (1): 37–58. doi:10.1080/00033799400200121.
  • David Strauss, Percival Lowell: The Culture and Science of a Boston Brahmin (Cambridge: Harvard University Press, 2001)
  • William Graves Hoyt, Lowell and Mars (Tucson: University of Arizona Press, 1976)
  • William Lowell Putnam, The Explorers of Mars Hill: A Centennial History of Lowell Observatory, 1894-1994 (New Hampshire: Phoenix Publishing, 1994)

External linksEdit

Historic American Buildings Survey (photographic survey)Edit