If you are interested in the hobby of astronomy, you know the key role many U.S. observatories play in advancing the space sciences and understanding our universe. From ground-breaking discoveries to monitoring near-Earth asteroids, the research being done by astronomical observatories is essential.
In addition to their scientific importance, observatories make great tourist destinations, offering activities and educational information to visitors as they tour the facilities and learn more about astronomy and space. The next time you travel, think about looking for astronomy-related activities to see while you are there.
We have put together a list of nine U.S. observatories with the most cutting-edge technology, significant public outreach, and noteworthy astronomical discoveries.
- Lowell Observatory
- Griffith Observatory
- Maunakea Observatory
- McDonald Observatory
- Kitt Peak Observatory
- Palomar Observatory
- Lick Observatory
- Yerkes Observatory
- Mount Wilson Observatory
While there is a summary included below for your information, be sure to check the observatory’s website for updated schedules and visitor information before planning a visit.
Most observatories on this list are located in or around the southwest. This is because of their favourable conditions for astronomical research, including:
- Higher Altitude: provides a thinner atmosphere, more stable air, and better seeing conditions
- Remote location: darker skies, away from light pollution
- Dry climate: less water vapour which is responsible for cloud formation, means more clear nights
1) Lowell Observatory
- State: Arizona
- Address: 1400 West Mars Hill Rd., Flagstaff AZ, 86001
- Elevation: 7,740 ft. above sea level
- Bortle Class: 4
- Year Opened: 1894
- Telescopes: Lowell Discovery Telescope (4.3 metre), Dyer Telescope (24-inch), Clark Refractor (24-inch) and more.
- Programs: Historical tours, open houses, science talks, demonstrations, stargazing, and special events
Founded in 1894, the Lowell Observatory is one of the oldest observatories in the United States. They operate multiple research telescopes on three campuses (Happy Jack, Anderson Mesa, Mars Hill) in northern Arizona. Current research includes the Sun, planets, comets, asteroids, life cycles of stars, planetary systems, galaxy exploration, and dark matter.
It is perhaps most famous for the discovery of Pluto, which helped to establish Lowell as a leading centre for planetary research. In addition to Pluto, Lowell also played a key role in preparing for the Apollo Moon missions as artists teamed with scientists to create detailed lunar maps.
It is home to the Clark Refractor, one of the most storied telescopes in the world and an important piece of American history. It also houses the Lowell Discovery Telescope (LDT), the fifth largest optical telescope in the United States, and one of the most versatile telescopes in the world.
As a leader in dark sky protection, Lowell was responsible for urging City Council to create a lighting ordinance in 1958 (the first in the world) to protect their sky quality. Flagstaff would later be named the world’s first International Dark Sky City because of their efforts and commitment to protecting dark skies.
Lowell Observatory | NorrisLW Photography
2) Griffith Observatory
- State: California
- Address: 2800 East Observatory Rd., Los Angeles, CA 90027
- Elevation: 1,134 ft. above sea level
- Bortle Class: 8-9
- Year Opened: May 14, 1935
- Telescopes: Zeiss Telescope (12-inch), Coelostat & Solar Telescopes
- Programs: Planetarium shows, solar viewing, staff talks, exhibit galleries, free public telescope viewing (on the roof and lawn).
Griffith Observatory is famous for its unique location atop the southern slope of Mount Hollywood. It is the most visited public observatory in the world with 1.6 million visitors each year. Over the years, it has become a cultural icon, being featured in several movies and television shows.
It is named after Griffith Jenkins Griffith, who donated 3,015 acres of land to the City of Los Angeles in 1896. He specified the purpose and features of the building in his will with the caveat that it be a ‘place for the masses’ with no admission charge.
In addition to free admission, the observatory offers free public telescope viewing each clear night (when open) to help educate the public. As a result, more than 8 million people have looked through the observatories refractor telescope, which is more than any other telescope in the world.
When it opened in 1935, it was the first facility in the U.S. dedicated to public science. It operated continuously until January 2002 when it closed for a $93 million expansion. After restoring and enhancing the ability to pursue its public mission, it reopened November 2006.
The observatory is part of a larger park, known as Griffith Park, which has golf courses, a zoo, and offers activities like hiking, bike rentals, horseback riding, tennis, and swimming.
3) Maunakea Observatories
- State: Hawai’i
- Address: Mauna Kea Access Rd. Hilo, HI 96720
- Elevation: 13,796 ft. above sea level
- Bortle Class: 2
- Year Opened: 1956
- Telescopes: 13 telescopes, including Keck I and ll, which are twin 10-meter telescopes
- Programs: Stargazing programs, educational programs, astronomy workshops, online resources
The summit of Maunakea, on the Big Island of Hawai’i, is home to some of the most productive telescopes in the world. On top of a dormant volcano sits the worlds largest astronomical observatory, which includes 13 observatories with telescopes operated by astronomers from 11 different countries.
Its location, which includes high altitude, gentle slopes, calm air and dark skies, makes it a premier site for astronomical research and provides the clearest visibility on Earth for observation.
Observatories Map | Love Big Island
To honour traditional practices and the cultural importance of Maunakea, the ‘A Hua He Inoa’ program at the University of Hawai‘i works closely with experts in Hawaiian language to weave traditional indigenous practices into naming astronomical discoveries on the island.
Still, the Maunakea Observatories have been the subject of controversy within the local community, voicing concerns regarding the respect for Hawaiian cultural beliefs, protection of environmentally sensitive habitat, and recreational use of the mountain.
There have been many important scientific discoveries using data from Maunakea, including:
- Revealing a supermassive Black Hole in the heart of the Milky Way galaxy
- Recording the first images of a planetary system orbiting another star
- Discovering the accelerated expansion of the Universe as a result of dark energy
While visiting the Maunakea Observatories in Hawaii is free, the journey to the summit can be challenging and may require a private tour. The actual observatories at the top of the summit are not open to the public.
Two observatories on Maunakea | Big Island Guide
4) McDonald Observatory
- State: Texas
- Address: 3640 Dark Sky Dr., Fort Davis, TX 79734
- Elevation: 6,235 – 6,800 ft. above sea level
- Bortle Class: 2
- Year Opened: May 5, 1939
- Telescopes: Hobby-Eberly Telescope (10-metre/393 inch), Harlan J. Smith Telescope (2.7 metre/107 inch mirror), Otto Struve Telescope (2.1-metere/82-inch) and more.
- Programs: Public tours, solar viewing, star parties, teacher resources, student activities, StarDate radio program, StarDate magazine
McDonald Observatory is operated by the University of Texas (UT) at Austin and is considered one of the world’s leading centres for astronomical research and education. It is located on Mount Locke and Mount Fowles in the Davis Mountains in West Texas.
The observatory is home to world leading equipment, including the Hobby-Eberly Telescope, one of the largest optical telescopes in the world. Using this technology, their research focuses on a broad range of astrophysical topics, such as exoplanet detection, star formation, and dark matter.
Some of the noteworthy discoveries include:
- the first detection of an atmosphere for any moon in the Solar System (Saturn’s moon, Titan)
- the development of a system for measuring star colour to remove the effects of interstellar dust
- the discovery of the first planet orbiting a binary star system using the Hobby-Eberly Telescope.
The observatory also has a lot of great outreach and informative displays – things like preserving dark skies exhibits, interactive displays about how they use the telescopes, and an amphitheatre for presentations and outreach events.
Similar to the Griffith Observatory, a banker (William J. McDonald) left a bulk of his fortune to the UT Austin with the purpose of aiding in the study and promotion of astronomical science.
5) Kitt Peak Observatory
- State: Arizona
- Address: Kitt Peak National Observatory, Arizona 85735
- Elevation: 6,877 ft.
- Bortle Class: 2
- Year Opened: 1964
- Telescopes: 21 optical telescopes, 2 radio telescopes
- Programs: Daytime tours, The Nightly Observing Program (NOP), Overnight Telescope Observing Program (OTOP), Remote Imaging Program
Kitt Peak Observatory is located west of Tucson on leased land from the Tohono O’odham Nation. It is home to the largest and most diverse collection of research telescopes located in one place in the world.
Of the nearly two dozen telescopes, three of them are dedicated to public viewing in their nightly stargazing programs. It also includes operating large instruments, like the Mayall 4-meter telescope and the WIYN 3.5-meter telescope, in partnership with other organizations/institutions.
For $199 USD, you can even rent time on a Parallax Instruments 12.5-inch Ritchey–Chrétien through their Remote Imaging Program.
Kitt Peak is famous for having the first telescope used to search for near-Earth asteroids and determining whether they would impact Earth. And in 1976, the Mayall telescope was used to discover methane ice on Pluto.
Current astronomical research at the observatory includes the study of dark matter, cosmic distances, high-redshift galaxies.
Kitt Peak Observatory | KPNO/NOIRLab/NSF/AURA/T. Slovinský
6) Palomar Observatory
- State: California
- Address: 35899 Canfield Rd., Palomar Mountain, CA 92060-0200
- Elevation: 5,617 ft.
- Bortle Class: 4
- Year Opened: 1948
- Telescopes: Hale Telescope (200-inch/5.1-meter), Samuel Oschin Telescope (48-inch/1.2-meter), Palomar 60-inch/1.5-meter Telescope, 30 cm (12 in) Gattini-IR
- Programs: Self guided and guided tours
The Palomar Observatory is located on Palomar Mountain in north San Diego County and is operated by the California Institute of Technology (Caltech). Research partners at the observatory include the Jet Propulsion Laboratory (JPL), Yale University, and the National Optical Observatories of China.
George Hale, who built the largest telescope in the world four times in a row (at Yerkes and Mount Wilson), was the visionary behind the Palomar Observatory. In choosing the site, he wanted to solve the problems experienced at Mount Wilson, which was the amount of light pollution from the city of Los Angeles.
The famous 200-inch reflecting telescope, named after Hale, saw first light in 1949 on NGC 2261and was operated by Edwin Powell Hubble. This telescope would be the largest in the world from 1949 until 1975.
In addition to the Hale Telescope, the facility has two other active telescopes that focus on scientific advancement, instrument development, and student training. Noteworthy discoveries include:
- Observations that led to the identification and understanding of quasars, which are bright and distant celestial objects powered by supermassive black holes at the centre of galaxies.
- Discovery and study of supernovae that have helped identify and characterize different types of supernovae and contributing to our understanding of stellar evolution and the expansion of the universe.
- Contributed to the study of exoplanets, including monitoring and characterizing through various observational methods (i.e. radial velocity measurements and transit observations).
Palomar Observatory | Palomar Observatory/Caltech
7) Lick Observatory
- State: California
- Address: 7281 Mount Hamilton Rd., Mount Hamilton, CA 95140
- Elevation: 4,209 ft.
- Bortle Class: 4
- Year Opened: 1888
- Telescopes: Shane (3-m) Telescope, Automated Planet Finder (2.4-m) Telescope, Nickel (1-m) Telescope and Coudé Auxilliary Telescope
- Programs: Exhibits, staff talks, self-guided and public tours, teacher training workshops, private events and weddings
The Lick Observatory is located on Mount Hamilton, east of San Jose, California. It was the world’s first permanently occupied mountain-top observatory.
It is owned and operated by the University of California (UC) and serves astronomers across the nine UC astronomy campus, including Berkeley, Davis, Santa Cruz, Los Angeles and San Diego.
The observatory offers unique outreach programs, including their ‘Evening with the Stars’ program, which features lectures by astronomers with views through a 36-inch refractor, and their ‘Music of the Spheres’ concerts that blends musical performances with astronomer-lead lectures.
Lick has contributed to many studies, including:
- Surveys and observations to map the distribution and motions of stars and gas to understand its structure and evolution.
- Discovery and characterization of exoplanets, including one of the first known exoplanets around a Sun-like star (51 Pegasi b)
- Studies in stellar spectra, which provide valuable insights into the properties and compositions of stars.
Like many of the observatories on this list, with the growth of nearby cities, light pollution continues to be a big issue. The City of San Jose began a program to replace all the streetlamps with low pressure sodium lights to reduce their effects and allow Lick to continue to be a viable location for space exploration.
Lick Observatory | Simon Davison
8) Yerkes Observatory
- State: Wisconsin
- Address: 373 W. Geneva St., Williams Bay, WI 53191
- Elevation: 1,096 ft.
- Bortle Class: 4
- Year Opened: 1897
- Telescopes: Yerkes Great Refractor (40 inch/102m), 40-inch/102 cm and 24-inch/61 cm reflecting telescopes
- Programs: Individual and group tours, speaker series, private events (weddings and business meetings)
The Yerkes Observatory is known as the birthplace of modern physics thanks to George Ellery Hale, a young astrophysics professor at the University of Chicago and founder of the observatory.
For the better part of a century, this observatory featured world-renowned astronomers conducting their research using the world’s largest refracting telescope, the Yerkes Great Refractor. The observatories reputation in the field of astrophysics may have also lead to hosting the famous Albert Einstein on his first trip to America.
At the Yerkes Observatory:
- Sherburne Burnham cataloged 13,665 star systems
- Edward Barnard discovered the large dark clouds of the Milky Way
- Edwin Hubble photographed the first evidence of the expansion of the universe
- Nancy Grace Roman, NASA’s first Chief of Astronomy, did her graduate work here, as did Carl Sagan
- The Morgan–Keenan (MK) star classification system was introduced by William Morgan, Philip Keenan, and Edith Kellman
Today, research is no longer conducted at the observatory and the University of Chicago closed the doors to the public October, 2018. The land was sold to a developer but plans fell through. The non-profit Yerkes Future Foundation (YFF) negotiated to save the observatory and the transfer of ownership, which included fifty acres and all buildings on site, took place on May 1, 2020.
The observatory remains an important part of astronomical history with a focus on public education and outreach for science, arts, and culture.
Yerkes Observatory | Lake Geneva
9) Mount Wilson Observatory
- State: California
- Address: Not available. Coordinates: 34°13′30″N 118°03′26″W
- Elevation: 5,710 ft.
- Bortle Class: 5
- Year Opened: 1904
- Telescopes: Snow Solar Telescope, Hooker Telescope (100-inch/2.5 m), 60-inch telescope,
- Programs: Tours, lectures, concerts, public ticket nights, art exhibitions, free public star parties, STEM education programs
The Mount Wilson Observatory is located in the San Gabriel Mountains, northeast of Los Angeles. It was founded by George Ellery Hale, who was responsible for the planning/construction of several world-leading telescopes, including the 40-inch telescope at Yerkes and the 200-inch telescope at Palomar.
The observatory is home to the Hooker Telescope, which was used by Edwin Hubble to determine that the Andromeda Nebula and Triangulum Nebula were not nebulae at all, but entire galaxies outside the Milky Way. This discovery changed the scientific view of the universe.
Currently, research on site has slowed down since the introduction of the 200-inch telescope at Palomar with many astronomers shifting their research studies to southern California.
However, they offer a variety of unique public outreach events, such as their concert series and art exhibitions. The observatory also offers a two-week college/university-level hands-on workshop in observational solar and stellar astrophysics.
You can also rent time on two of the largest telescopes available for public use, the Hooker telescope and the 60-inch telescope. Rates are upwards of $2,500 USD for a half night session for a group up to 20 people.
Mount Wilson Observatory | Discover Los Angeles