Hall 42-inch Telescope

This 1.1-meter (42-inch) fork-mounted telescope has been a workhorse telescope at Lowell’s Anderson Mesa dark-sky site for more than half a century. It is named after John S. Hall, fifth director of Lowell Observatory (and no relation to current Director Jeff Hall). The telescope came about as a replacement for the 42-inch Lampland Telescope, which was housed on Mars Hill in the dome affectionately called the Jiffy Pop dome by staff members, due to its similar appearance to the popular popcorn product.

The Hall Telescope and dome were built in 1968-69, and regular use began in 1970 and has continued to the present. The telescope is located on an upper floor, and the dome features a catwalk that allows astronomers to easily go outside to check on weather conditions. The telescope has an f/8 Ritchey-Chretien optical configuration and was upgraded in 2004 with a lightweight Hextek primary mirror, thanks to funding from the John M. Wolff Foundation and the Friends of Lowell Observatory.

The Hall Telescope is optimized for CCD imaging, photoelectric photometry, and spectroscopy. Three primary instruments have been mounted on the telescope in recent years.

  • One is a NASA-funded CCD camera, which Dave Schliecher and his comet research team use to study the motion and rotational period of comets and asteroids.
  • The Kron Photometer, named for long-time Lowell supporters Gerald and Katherine Kron, is used for compositional studies of comets.
  • The NSF-supported Solar-Stellar Spectrograph (SSS), was used for long-term comparative studies of the Sun and Sun-like stars.


  • Diameter: 1.04 m (42 inches)
  • Effective Focal Length: 8.39 m
  • f/ratio: 8.06

Other Lowell Telescopes & Facilities

See More