The 1.5-meter reflector AZT-12 is the largest optical telescope in Northern Europe. It was manufactured in Leningrad (now Saint Petersburg) by LOMO (Russian: Ленинградское Oптико-Mеханическое Oбъединение, lit. 'Leningrad Optical Mechanical Association') and installed at Tartu Observatory in 1974-1975. The telescope was officially opened for astronomical observations on October 21, 1976. Telescope control system was automated in 2011.
Parameters of the telescope
|Main Mirror||Primary focus||Guide|
|Diameter||1.5 m||Focal length||52.8 m||Diameter of objective||0.3 m|
|Radius of curvature||-10554.69 mm||Focal ratio||1/3.51||Focal length||4 m|
|Weight||850 kg||Field of view||0.07°||Magnification||max x400
|Primary-to-secondary distance||4144.31 mm||Cassegrain focus||Field of view||0.1°–0.6°|
|Secondary mirror||Focal length||24 m||Finder|
|Diameter||0.36 m||Focal ratio||1/16||Diameter of objective|
|Radius of curvature||-2904.57 mm||Field of view||0.34°||Focal length|
|Conic value e2||2.444605||Plate scale||116 μm/''||Magnification||max x18|
|Coudé focus||Field of view||2.5°|
|Height of the telescope||7.26 m||Focal length||52.8 m|
|Length of the tube||6.5 m||Focal ratio||1/35.2|
|Diameter of the dome||15 m||Field of view||0,083°|
Since mid-80s the main instrument has been the longslit spectrograph ASP-32 (also manufactured by LOMO), which has 10 exchangeable diffraction gratings for 300–1100 nm wavelenth range.
|Grating (lines/mm)||Single exposure coverage (Å)||Dispersion
Camera Andor Newton DU970
– 1600x200 pix, 16 μm/pix
– Cooled thermoelectrically to -90 °C
At present, the telescope is used mostly for the observations of variable stars by researchers of the Department of Stellar Physics.