The ZTA-2.6 Telescope at Byurakan Observatory

Earlier I wrote about the 1-meter Schmidt telescope at the Byurakan Observatory. Today I want to focus on another giant of Armenian and Soviet science — the ZTA-2.6 telescope. For anyone interested in Soviet technology, scientific tourism or into urbex adventures, this site is a true hidden gem. And yes — you can explore it on my urban explorer tours across Armenia.

The Byurakan Observatory stands on the southern slope of Mount Aragats, in the village of Byurakan, Aragatsotn Province, about 50 km north of Yerevan, at an altitude of around 1,500 meters. It is one of the most significant scientific centers of the Soviet era.

Aerial photo of the building that houses the ZTA-2.6 telescope

The ZTA-2.6 telescope was built by LOMO (Leningrad Optical-Mechanical Association, St. Petersburg, Russia) and later transported to Armenia by plane. Not all large telescopes could handle such a journey. For example, the Schmidt telescope could not be flown due to its fragile optical system. Even the slightest vibration might have ruined its components, so it had to be delivered by truck at a cautious speed of no more than 15 km/h.

Winter in Byurakan Astrophysical Observatory

ZTA-2.6 is, in fact, the twin of the G. A. Shain reflector at the Crimean Astrophysical Observatory. Both instruments, as well as the famous 6-meter telescope at the Russian Special Astrophysical Observatory, were designed by Bagrat Ioannisian, LOMO’s chief constructor.

The observatory’s building itself is iconic. Designed by architect Sargis Gurzadyan and completed in 1975, it became operational in 1976 when the first observations were carried out.

The Control Panel of the ZTA-2.6 Telescope

The ZTA-2.6 telescope is the largest instrument at the observatory. It sits near Byurakan at 1,406 meters above sea level.

Main specifications:

Primary mirror diameter: 260 cm
Mirror weight: 4 tons
Mirror material: Sitall
Mounting: Equatorial
Aperture ratio (D/F): 1:3.85

Optical parameters:

Primary focus: 10 m focal length, 2′ field
Cassegrain focus: 40 m focal length, 4′ field
Nasmith foci (3): 40 m focal length, 12′ field
Coudé focus: 105.4 m focal length, 1′40″ field

This 80-ton ZTA-2.6 telescope rotates on 60-micron-thick oil pads

Today, the telescope has been fully modernized. The original control panels, once essential, are now retired, preserved as silent witnesses of another era. The system is fully computer-controlled: scientists simply enter the galactic coordinates, and the telescope automatically adjusts to the desired position.

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