Look up and out of the sunspot
Sunspot, an aptly named community in southwestern New Mexico, is home to two large astronomical observatories. The Sunspot Solar Observatory and Apache Point Observatory are located on the peak of Sacramento at an elevation of 9,200 feet (2,800 meters), high enough to give telescopes a clearer view of objects in space by reducing interference from airborne particles called aerosols. The high altitude also offers visitors a panoramic view of the Chihuahuan Desert and the vast gypsum sand dunes.
The observatories and dunes can be seen in the above natural color image, which was captured by the Operational Land Imager (OLI) on Landsat 8 on September 16, 2021. Although this part of New Mexico is generally dry , the observatories are located in a rugged woodland area kept green by high altitude rainfall and a network of perched aquifers that keep water above the regional water table. The only road leading to Sunspot is New Mexico State Road 6563, named after H-alpha, a dark red spectral line with a wavelength of 656.28 nanometers. This wavelength is useful for observing the main characteristics of the Sun’s atmosphere.
The Sunspot Observatory is home to the Dunn Solar Telescope, a high-resolution, vertical-axis telescope used to study solar cycles, sunspots, and flares. A heliostat atop a 136-foot (41-meter) concrete tower directs sunlight downward toward a primary mirror that is deep underground.
The Apache Point Observatory has several telescopes used for astrophysical research. Among them is a 2.5-meter optical telescope used as part of the Sloan Digital Survey, an ambitious sky mapping project that produced the largest three-dimensional map of the universe ever made. The map includes approximately two million galaxies and quasars that span 11 billion years of cosmic time.
Apache Point also houses a 3.5-meter telescope with a lunar telemetry system. Astronomers use pulses from the observatory’s lasers and a retroreflector on the Moon (left there by the Apollo astronauts) to measure the distance between Earth and the Moon to within a few millimeters. The system is used to study the interior structure of the Moon, general relativity, gravity, and the nature of space-time.
In 2021, the Apache Point Observatory Telemetry Station joined NASA’s Space Geodesy Project, an effort to create celestial and terrestrial reference frames, systems that assign coordinates to locations on Earth and in the ‘space to provide a coherent framework for linking measures to each other.
Accurate reference frames are essential for Earth observation satellites to accurately map subtle changes in the Earth’s surface, maintain global positioning systems (GPS), and facilitate satellite navigation.
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the US Geological Survey. Story of Adam Voiland.