The ETSU Observatory, located on the hill behind campus. Under the dome is a 14 inch diameter Celestron telescope. The telescopes outside are 8 inch diameter Meade telescopes. These are all Cassegrain focus reflecting telescopes.

East Tennessee State University is one of the five Universities in the Southeastern Association for Research in Astronomy (SARA), which operates this 0.9 meter (36 inch) telescope at Kitt Peak in Arizona. The SARA telescope is often operated remotely from the eastern US.

Kitt Peak contains a large number of telescopes, in addition to the SARA telescope. Most of these telescopes are operated by the National Optical Astronomical Observatories (NOAO), a public facility for professional astronomers from all over the US. The telescope shown on the right is the Kitt Peak 4m telescope.

This is the brand new 8.1m Gemini North telescope built by the US (NOAO), in collaboration with the United Kingdom, Canada, Chile, Australia, Argentina, and Brazil. It is located on Mauna Kea, in Hawaii. It was dedicated in June 1999, and began general observations in June 2000. The matching Gemini South 8.1m telescope is located on Cerro Pachon in central Chile.

The Gemini mirror.

The Hubble Space Telescope has a 2.4 meter mirror, and has instruments that operate at ultraviolet, optical, and infrared wavelengths.

The National Radio Astronomy Observatory 100 meter telescope was recently built in Green Bank, West Virginia.

The 300 meter Arecibo radio telescope, in Puerto Rico. It is built into a valley, and is not steerable.

The Very Large Array in New Mexico: a collection of 27 radio telescopes, each with diameters of 25 meters, covering up to 22 miles. Working together, these provide very high resolution.

The Kuiper Airborne Observatory. A Lockheed C-141 aircraft which carried a 0.9 meter optical/infrared telescope. This observatory was run by NASA, and operated from 1974 - 1995.

The Stratospheric Observatory for Infrared Astronomy (SOFIA). A planned 2.5 meter telescope to be housed in a Boeing 747-SP aircraft. This telescope will begin operations in the year 2002. It is a collaborative project between the US (NASA) and Germany.

The transparency of the Earth's atmosphere at different wavelengths. In Gamma rays, X-rays, and ultraviolet, nearly all the light is blocked by the Earth's atmosphere. At only certain infrared wavelengths does light get through the Earth's atmosphere. At radio waves, the atmosphere is transparent, except at wavelengths longer than 100 meters.