Photo: the 24″ Dyer telescope, being tested by Lowell staff | Danielle Adams, 2020
Co-Written with Jim Cole, Senior Public Program Educator
The Dyer telescope is the newest addition to Mars Hill’s suite of telescopes, having been installed just a few months ago in February of 2020. Since Lowell Observatory made the difficult decision to close down its public program at the onset of the COVID-19 pandemic, the Dyer hasn’t gotten to see much action beyond training sessions with staff. Fortunately, Mars Hill’s newest telescope is now available for public viewing during a brand new, private stargazing experience. Though not quite as tenured or storied as the 125-year-old Clark Refractor, the Dyer is sure to build a legacy of its own as it creates incredible experiences for a new generation of stargazers.
A Bit of History
Visitors to the observatory may recall visiting the McAllister Dome, located just a stone’s throw from the Clark Dome. Until the end of 2019, the dome housed the McAllister Telescope, a 16” Boller and Chivens cassegrain telescope that was manufactured in 1966. It was used as a student research telescope at Northwestern University in Illinois until it was donated to Lowell Observatory for public viewing in 1995.
In 1999, the telescope became operational with the help of a generous donation from Frances Burt McAllister, which funded the construction of a dome to house the telescope on Mars Hill. The dome was christened the John Vickers McAllister Dome, after Frances’s husband, and the scope itself became known as the McAllister Telescope.
A Shiny New Arrival
With the McAllister Dome empty of its former tenant, Lowell staff could prepare for a new arrival. The dome, which had undergone few updates since its original construction, was refurbished to accommodate a brand new, state-of-the-art Planewave 24” CDK Astrograph mounted on a Planewave L-600 Direct Drive mount. CDK stands for Corrected Dall-Kirkham optical design, meaning that the telescope utilizes an elliptical primary mirror and spherical secondary mirror.
The Dyer’s mirrors are made of fused silica and are supported by carbon fiber trusses. The scope has a focal length of 3974 mm (156.5 inches). With its 24” aperture, the focal length yields a focal ratio of f/6.5. The 30mm 82° eyepiece provides a maximum 0.6° field-of-view, which is slightly larger than the size necessary to accommodate the Sun, or the full Moon. The telescope is very well-suited for viewing smaller objects like planets, globular star clusters, smaller open star clusters, and small to medium nebulae and galaxies.
Currently, the telescope is set up for visual use only, but in the near future will be upgraded to include a motorized focuser, a field de-rotator, and an instrument cube that will allow scientific work to be done when the telescope is not being used for public viewing. The Dyer Telescope was named for Brian Dyer, a friend and business partner of the donors.
This new telescope is the subject of an exciting new stargazing experience here at Lowell Observatory: Dyer Premium Access. Similar to Giovale Open Deck Observatory (GODO) Premium Access, this experience grants groups of up to 10 cohabitating or co-traveling individuals to enjoy 75 minutes of private stargazing through the Dyer telescope. Because of the scope’s advanced technology, our specially trained educators can offer a dazzling variety of celestial objects for viewing.
Unveil the universe and take your stargazing to the next level, reserve a Dyer Premium Access experience today!