A holy place for stargazing in the dark night: How “hardcore” is Mount Lemmon Observatory?

Author: Du Lian

Audit│Ding Yi

Editor: Zhao Jingyuan

Mount Lemmon Observatory is located on Mount Lemmon northeast of Tucson, Arizona, USA, at an altitude of 2,791 meters. It was built in 1954. The observatory was originally a radar station, but was later transferred to the Steward Observatory of the University of Arizona in 1970 and converted into an infrared observatory.

Mount Lemmon Observatory. Image source: Wikipedia

After decades of development, the Mount Lemmon Observatory now has multiple facilities.

The 1.52-meter (60-inch) Steward Observatory Telescope is a Cassegrain reflecting telescope and part of the Catalina Sky Survey (CSS), whose primary purpose is to discover and monitor (near-Earth) asteroids, supernovae, etc. It was built in the late 1960s and was originally installed at the Steward Observatory Catalina Station on Mount Bigelow, before being moved to Mount Lemmon in 1972. The instrument has a parabolic primary mirror with a switchable secondary mirror that can switch between two Cassegrain foci at f/16 and f/45, and a CCD-mosaic camera at the prime focus at f/2, capable of capturing objects as faint as magnitude 21.5 with a wide field of view of 1 degree, which is used routinely by the Catalina Sky Survey. The Catalina Sky Survey also has two public science projects, called The Daily Minor Planet and The Great Supernova Hunt, for the public to search for asteroids and supernovas from the scientific data obtained from the project. Interested parties can participate: https://www.zooniverse.org/projects/fulsdavid/the-daily-minor-planet, http://nesssi.cacr.caltech.edu/SNhunt/.

Steward Observatory telescope. Image credit: University of Arizona

The University of Minnesota Mount Lemmon Observatory Facility (UMN-MLOF) is also a 1.52-meter Cassegrain reflecting telescope, similar in structure and design to the Steward Observatory telescope. The telescope observes in the optical and near-infrared bands and played a vital role in the pioneering development of infrared astronomy in the 1970s, when Mount Lemmon was the highest infrared observatory in the North American continent.

The 1-meter Catalina Sky Survey Reflecting Telescope (CSS Reflecting Telescope) is also part of the Catalina Sky Survey. It was originally located at the Catalina Observatory of Steward Observatory and then moved to Mount Lemmon Observatory in 1975. The telescope is used for follow-up observations of newly discovered near-Earth objects.

The 0.8-meter Schulman Telescope is the world's largest public telescope, using a Ritchey-Chrétien (RC) optical system. It was donated to the Mount Lemmon Sky Center by the Schulman Foundation. The public can use this device on-site or remotely under the guidance of staff.

The Shulman telescope. Image source: Reference 6

In addition, Mount Lemmon Observatory also has many facilities, including the 1-meter KASI automated telescope of the Korea Astronomy and Space Science Institute (KASI), the 0.6-meter Manna telescope of the University of Louisville, etc.

Aerial view of Mount Lemmon Observatory. Image credit: Astronomy Camp

Today, Mount Lemmon Observatory also has observation, research and exploration projects open to the public. In 2008, the University of Arizona established the Mount Lemmon Sky Center, which is affiliated with Steward Observatory and the Department of Astronomy at the University of Arizona. It is committed to enhancing people's interest in science and astronomy through high-quality education and public experience. The center will hold various astronomical observations and lectures from time to time, and will also carry out some very interesting public projects, such as SkyNights and AstronomerNights. The SkyNights project provides the public with resources such as astronomical lectures, star maps, binoculars and Shulman telescopes; the AstronomerNights project allows several visitors to use the Shulman telescope for a long time under the guidance of staff, obtain observation images and process the images, and live in the observatory's dormitory. The rich activities and good atmosphere have made Mount Lemmon Observatory a check-in destination for many astronomy enthusiasts.

The Mount Lemmon Sky Center's "Sky Nights" program. Image credit: Visit Tuson

References

1. Mt.Lemmon Infrared Observatory--Altitude 2800m (9157 feet), Astronomy Camp, http://www.astronomycamp.org/pages/lemmon.html

2. About Us, Mount Lemmon SkyCenter, https://skycenter.arizona.edu/content/about-us

3. History, The University of Arizona, https://skycenter.arizona.edu/content/history

4. The Schulman Telescope, The University of Arizona, https://www.as.arizona.edu/schulman-telescope

5. Mount Lemmon Observatory, wikipedia, https://en.wikipedia.org/wiki/Mount_Lemmon_Observatory

6. Mount Lemmon Sky Center's 'Sky Nights' Observing Program, http://scopeviews.co.uk/MtLemmonSkyCenter.htm

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