Completed in 1969, the telescope was upgraded with high-order adaptive optics in 2004 and remains a highly versatile astrophysical observatory that serves as an important test platform for developing new instrumentation and technologies.

The telescope's entire optical system – from the top of the tower to the base of its underground portion, plus the 40-foot-diameter (12 m) observing room floor – is contained within the vacuum tube.

The optics are evacuated to eliminate distortion due to convection in the telescope that would otherwise be caused by the great heat produced by focusing sunlight.

The Dunn Solar Telescope has a rotating optical bench, which can be configured to multiple observing setups, depending on the requirements of the science under study.

The instrument samples adjacent slices of the solar surface using four parallel slits to achieve high cadence, diffraction-limited, precision spectropolarimetry.

Completed in 2005, it was designed to act as 'experimental oriented' instrument, built with a flexibility to allow for the combination of any many spectral lines, "limited only by practical considerations (e.g., the number of detectors available, space on the optical bench, etc.)".

In addition, some older instruments are available, although these are now rarely used: A design for a Solar Vacuum Tower Telescope was started by the architect and engineer Charles W. Jones in 1963.

Construction on the final building started in 1966 under the U.S. Army Corps of Engineers and ended in 1967, at a cost of about $3 million, with the architectural firm of Roghlin and Baran, Associates.

Also, it provides the comfort of a heated observing room [...]"[14] The tower telescope was originally dedicated on October 15, 1969, and renamed in 1998[15] after Richard B.

[16] A plaque at the facility reads: "Named in honor of one of solar astronomy's most creative instrument builders, this vacuum tower telescope is the masterpiece of Richard B. Dunn's long scientific career at Sacramento Peak Observatory (1998).