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1.5-meter telescope of Tartu observatory

* 58°15’56.7″ North * 26°27’34.9″ East *
1.5-m telescope		 Telescope scheme
See larger scheme

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 
Diameter
Radius of curvature
Weight

1.5 m 
-10554.69 mm
850 kg

Primary-to-secondary distance
 
4144.31 mm
Secondary mirror 
Diameter
Radius of curvature
Conic value e2

0.36 m 
-2904.57 mm
2.444605   

Height of the telescope
Length of the tube
Diameter of the dome
 
7.26 m
6.5 m
15 m
Primary focus 
Focal length
Focal ratio
Field of view

5.28 m
1/3.51  
0.07°
Cassegrain focus 
Focal length
Focal ratio
Field of view
Plate scale

24 m
1/16  
0.34° 
116 μm/''
Coudé focus 
Focal length
Focal ratio
Field of view

52.8 m
1/35.2  
0.083°
Guide 
Diameter of objective
Focal length
Magnification   max
                min
Field of view

0.3 m
4 m
x400  
x71  
0.1°- 0.6°
Finder 
Diameter of objective
Focal length
Magnification   max
Field of view

0.1 m
1 m
x18 
2.5°

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
(Å/mm)
2400 247 10
1800 270 10.6
1200 750 29.3
600 2060 80.6
300 4500 175

Camera Andor Newton DU970
– 1600×200 pix, 16 μm/pix
– Cooled thermoelectrically to -90 C

In 2024 the spectrograph ASP-32 will be replaced by fiber-fed Echelle spectrograph Whoppshel with spectral resolution R = 30000