location: 40.32958295879448, 44.27005212860486

architect: Sargis Gurzadyan

date: 1976

The Large Telescope building houses the ZTA-2.6 reflector — the largest observational instrument at the Byurakan Astrophysical Observatory, located on the southern slope of Mount Aragats at an altitude of 1,406 metres above sea level. Both the instrument and the architecture make it exceptional: when installed in 1975, the ZTA-2.6 was the 7th largest telescope in the world. The building itself resembles a spacecraft, with a vast metal dome rising above a cylindrical body raised on inclined supports and wrapped in horizontal bands. Although conceived as a strictly scientific, non-public facility, it has become one of the emblematic, if less widely recognised, works of Armenian modernist architecture, where technological necessity and architectural expression converge in a single monumental form.

The close relationship between instrument and architecture had characterised observatories long before telescopes reached the dimensions of the great 20th-century reflectors. Astronomical instruments have always required precise orientation, stable supports, and carefully directed openings toward specific regions of the sky. Optical telescopes developed along two principal lines: refractors, which focus light through a large lens, and reflectors, which collect it with a curved mirror. As instruments increased in size, mirrors offered decisive advantages. Unlike lenses, which can only be supported at their edges, mirrors can be supported from behind and manufactured at much larger diameters. A larger mirror gathers more light, enabling astronomers to observe extremely faint objects — such as distant galaxies, dim stars, and active galactic nuclei — and to study them in greater detail. For this reason, large 20th-century optical telescopes were predominantly reflectors. Their increasing size required precise rotational mechanisms and, in turn, large rotating domes to protect and house the instrument. As mirrors, tubes, and mounting systems grew heavier and more complex, observatory buildings became increasingly massive and structurally stable, with the dome emerging as one of their most characteristic architectural elements.

Across the Soviet Union, an extensive network of astronomical observatories and high-altitude stations were established over the course of the 20th century, with a significant expansion after the Second World War, when large-scale scientific infrastructure became a priority of the Academy of Sciences. Within this network, the Caucasus and adjacent mountain regions became particularly important for observational astronomy because of their elevation, atmospheric clarity, and relatively stable observing conditions. Several major Soviet astronomical centres were concentrated here, including Abastumani in Georgia (1932), Byurakan in Armenia (1946), Shamakhi in Azerbaijan (1959), and the Special Astrophysical Observatory in the North Caucasus (1966). Together, they formed an important regional network for the development of Soviet astrophysics.

There was, however, no single architectural style for Soviet observatories. Telescope towers were more directly constrained by technology than most public buildings and often remained comparatively austere, while laboratories, administrative buildings, and residences more clearly reflected the architecture of their period. Thus, even a highly technical observatory could be Classical, national-romantic, or modernist in character. Byurakan provides an unusually clear example of this evolution within a single ensemble. Architect Samvel Safaryan, responsible for its first stage, conceived the observatory not as a collection of isolated technical structures but as a scientific settlement within a roughly ten-hectare garden. Low buildings were distributed across the plateau in relation to the landscape and distant Mount Ararat. The main research building and early telescope towers combined local stone and restrained ornament with forms recalling medieval Armenian architecture.

Later additions to the Byurakan Observatory increasingly adopted a modernist language. Their architect, Sargis Gurzadyan, became involved with the complex almost at the beginning of his career. After graduating in 1951, he worked in Safaryan’s studio, preparing drawings and architectural details for the earlier buildings before gradually designing a second generation of structures himself. These included the Small Telescope Tower (1954), a conference hall (1957), laboratory (1975) and workshops, and eventually the Large Telescope (1976). In contrast to Safaryan’s stone monumentality, Gurzadyan increasingly worked with reinforced concrete, glass, and more abstract compositions. Similar approaches can be seen in his other projects, including the Yerevan Cascade (1970s, with Jim Torosyan and Aslan Mkhitaryan), and the Polytechnic Institute complex in Yerevan’s Avan district (1980, with Karsata Matinyan, unrealised).

The ZTA-2.6 reflector brought an entirely new scale to the development of the observatory’s instrumental infrastructure. Its name refers to the 2.6-metre diameter of its primary mirror, which weighs around 4 tonnes. Designed by engineer Bagrat Ioanissian and manufactured by the Leningrad Optical-Mechanical Association, the telescope was essentially a twin of the 2.6-metre reflector installed at the Crimean Astrophysical Observatory in 1960. It was installed at Byurakan in 1975 and officially opened the following year. Its significance lay not in being an experimental prototype, but in giving Byurakan — already an internationally important centre of astrophysics — one of the world’s largest optical instruments of the time. Its large mirror collected enough light to examine selected and often very dim objects in much greater detail and to analyse their spectra. It was used to study active and Markarian galaxies, groups and clusters of galaxies, as well as young and variable stars, allowing astronomers to investigate individual targets much more closely.

This scientific capacity translated directly into architectural scale. The four-tonne mirror and its mounting had to move with extreme precision while remaining stable, and the surrounding building had to protect the instrument without transmitting vibrations that could interfere with observations. Gurzadyan placed the telescope inside a three-storey tower crowned by a rotating 60-ton duraluminum dome. Rather than concealing the machinery, the architecture emphasises it: the enormous dome remains visually distinct from the cylindrical body below, while inclined supports open the lower part of the structure and make its heavy upper volume appear almost suspended above the landscape.

You can explore the interior of the Large Telescope in a 360° virtual tour created by TUMO here.

Yet Gurzadyan did not treat this technological form as stylistically neutral. While designing the Large Telescope, he produced numerous studies inspired by the articulated, columned drum of the 13th-century Khorakert Church, where the cylindrical transition zone beneath the dome is rhythmically divided by a series of 30 engaged columns that both structure the wall surface and visually lighten the mass of the drum. The basic idea of an articulated circular drum carrying a dominant upper volume was translated into reinforced concrete and adapted to the scale of a modern astronomical instrument. This combination is characteristic of Gurzadyan’s broader work: modern materials and structural logic are used to reinterpret spatial and compositional principles of the Armenian architectural tradition. Even the surrounding paths, landscaping, entrances, and smaller architectural elements were considered as part of the project, integrating the telescope into the wider observatory ensemble.

The Large Telescope thus makes especially visible the relationship between science and architecture. Its fundamental geometry was dictated by the requirements of a highly specialised instrument, yet Gurzadyan transformed those constraints into an architecture specific to its place and period — simultaneously technological, modernist, and rooted in Armenian architectural memory. The ZTA-2.6 remains the largest observational instrument at Byurakan and continues to preserve both its original scientific function and the architectural form created for it half a century ago.

Sources and Further Reading

Castro Tirado, Miguel Ángel; Castro-Tirado, Alberto J. “The Evolution of Astronomical Observatory Design,” in: Journal of the Korean Astronomical Society, vol. 52, no. 4, 2019, p. 99–108. 

Grigoryan, Ashot. “Architectural Features of the Byurakan Observatory Complex,” in: Communications of the Byurakan Astrophysical Observatory, vol. 72, no. 1, 2025, p. 154–161. 

History of the Byurakan Astrophysical Observatory. Byurakan Astrophysical Observatory 

Most Important Facts about Byurakan Astrophysical Observatory. Byurakan Astrophysical Observatory

ZTA-2.6 Telescope. Byurakan Astrophysical Observatory

Byurakan Astrophysical Observatory (BAO). 70 years of Stellar Associations: International Conference, 25-27 September 2017