The dry air and mountains of Arizona and New Mexico make these states prime astronomical destinations. You have numerous options for astronomy-related excursions in this area; this post features seven observatories that are open to the public. Most of them offer tours, other activities, and/or visitor centers. In addition to their scheduled programs and activities, many of them will arrange group tours with sufficient advance notice and subject to availability.
Because these observatories are all at high elevations, as indicated below for each site, you might feel the altitude. Some of the observatories offer tours or other activities year-round, but a couple are accessible only in the summer and early fall.
Kitt Peak National Observatory, in southeastern Arizona near Tucson (6880 ft), is the main facility of the National Optical Astronomical Observatory in the US. It offers a wide variety of public programs and activities, including daytime tours, nighttime stargazing, exhibits at the visitor center, and astrophotography workshops. The telescopes here include older instruments such as the Mayall 4-meter telescope and a 2.1-meter (84-inch) telescope that Vera Rubin used to make some of her initial observations suggesting the existence of dark matter, the McMath solar telescope, and the relatively new WIYN telescope, with a clamshell design in which the entire building slides away to expose the telescope for observing.
While you’re in the area, you can also visit the Fred L. Whipple Observatory, which is part of the Smithsonian Astrophysical Observatory. The visitor center is in the tiny town of Amado (3100 ft), which is south of Tucson. Its exhibits include a 3D model of the distribution of galaxies in the universe. Outside the center, there’s a patio with a telescope and binoculars that anyone can use to spot telescopes on Mount Hopkins and Kitt Peak or to observe the surrounding scenery of desert and mountains. (The binoculars are wheelchair-accessible; as the observatory’s web site notes, this also makes them popular with small astronomers.) There’s also a picnic area and a night-time observing spot where amateur astronomers can bring their own telescopes and binoculars to do some stargazing under dark skies. Tours of the observatory itself, which is on Mt. Hopkins (8600 ft) in the Santa Rita Mountains, usually depart from the Visitor Center Monday, Wednesday, and Friday from mid-March through November. You’ll need to make a reservation in advance, and the tour lasts from 9am to about 3pm. The MMT is the main telescope at the observatory. It was originally a multiple-mirror telescope with six mirrors, each 72 inches (1.8 meters) in diameter, which gave it the equivalent light-gathering power of a 4.5-meter mirror. In the late 1990s, the telescope was redesigned with a single large mirror (6.5 meters). The new mirror was the first large mirror to be produced using an innovative technique at the Steward Observatory Mirror Lab of the University of Arizona in Tucson (which, by the way, offers tours).
(Incidentally, if you want to pack even more astronomy into your vacation in this part of the world, you can also visit the Grace Flandrau Science Center & Planetarium in Tucson.)
Mount Graham International Observatory (10,400 ft), in east-central Arizona, is the home of the Vatican Advanced Technology Telescope, a relatively small telescope that can outperform larger ones because of its unusual design; the Large Binocular Telescope, which has two 8.4-meter (27-foot) mirrors side by side under a single dome; and the Heinrich Hertz Submillimeter Telescope, which is part of the Arizona Radio Observatory. To visit Mt. Graham, you start in Safford, where day-long tours start at the Discovery Park Campus of Eastern Arizona College. Depending on the weather, tours are offered Saturday and Sunday between mid-May and October; you’ll need to make a reservation in advance. The tour includes a ride up the mountain, with a discussion of its geology, ecology, and history, followed by lunch at the top and a tour of the telescopes.
Lowell Observatory, in northern Arizona near Flagstaff (7,250 ft), was founded in 1894 by Percival Lowell, who commissioned the observatory’s Clark telescope for his studies of Mars. He was mistaken about the presence of canals on Mars, but his observatory has made some major contributions to astronomical research. For example, Indiana astronomer Vesto Slipher used the telescope to observe the spectra of galaxies and discovered that the light from galaxies was red-shifted, a major step in the discovery of the expansion of the universe. Clyde Tombaugh made the first recognized sighting of Pluto on a photographic plate taken by another of the observatory’s telescopes. The observatory also has a modern 4.3-meter telescope and other active research instruments. The Pluto telescope is currently being restored, but the observatory’s many programs and activities include opportunities to view the night sky through the Clark telescope, as well as tours and other daytime programs and a summer camp for kids.
In west-central New Mexico, the National Radio Astronomy Observatory’s Very Large Array, a beautiful array of 27 radio antennas, is located about 50 miles west of Socorro on the Plains of San Agustin (6970 ft). The radio telescopes lie along three arms in the shape of a Y, and the observatory can be reconfigured depending on astronomers’ needs by moving individual antennas along tracks. The Visitor Center will introduce you to the work of the observatory, and you can pick up a brochure that will guide you on a walking tour. On the first Saturday of every month, 45-minute guided tours are offered at 11:00am, 1pm, and 3pm. Tours are offered more often on the first Saturdays of April and October, when the observatory offers a free open house.
The National Solar Observatory at Sacramento Peak is located In the Sacramento Mountains east of Alamogordo, in southern New Mexico (9200 ft). Here you’ll find the Richard B. Dunn Solar Telescope (left), two other solar instruments, and the Sunspot Astronomy & Visitor Center, which includes exhibits about astronomy and a gift shop. The observatory is in the town of Sunspot (actually it pretty much is the town of Sunspot), which is near the village of Cloudcroft in the Lincoln National Forest. You’re welcome to walk around the peak, guided by a brochure that describes the telescopes, or you can contact the Visitor Center to find out when tours will be offered. The view of the Tularosa Basin and White Sands from the peak is memorable. (Sunspot is also the home of the sun in a solar system model that extends to New Mexico Museum of Space History in Alamogordo, New Mexico, where you’ll find Neptune.)
You can also visit Apache Point Observatory (9200 ft), which is not too far from the NSO facility at Sacramento Peak. This site is not as public-facing as some of the others mentioned here, but there are several great scopes here doing interesting work, and you’re welcome to take a self-guided tour and learn about them. This observatory, which began operation in 1990, is the newest of the seven I’ve described. One of its most noteworthy accomplishments is that a telescope here made the observations for the Sloan Digital Sky Survey, which provides a treasure trove of data (images, spectra, and redshifts) on stars, galaxies, and quasars.