2.6-m Shajn Telescope (ZTSh)


2.6-meter reflector ZTSh named after academician G.A. Shajn is the main optical telescope of CrAO. It was built in 1961 by the Leningrad Optical and Mechanical Association (LOMO). The chief designer was B.K. Ioannisiani.

Primary mirror diameter2.6 m
Focal length10 m
Optical systems: Primary focus (f/3.85),
Cassegrain focus (f/16),
Nasmyth focus (f/16)
Coude focus (f/40)
Equipment: Spectrograph SPEM in the Nasmyth focus
Spectrograph ASP-14 in the coude focus
Echelle spectrograph in the coude focus (ESPL)
CCD-camera in the primary focus
Coordinates44°43′41″ N;  34°00′57″ E


Spectrograph SPEM in the Nasmyth focus

Characteristics of the spectrograph

Collimatorf/16, D = 80 mm
Maksutov cameraf/2.5
Diffracting gratings651 и 1200 Grooves/mm (150×150 mm)
Dispersion near Hα line with grating of 651 gr/mm1.76 Å/pixel; 2465 Å per frame
Spectral resolution with the entrance slit width of 3″ and with grating of 651 gr/mm7.5 Å
Scale0.78 arcsec/pixel
Exposure for Seyfert galaxies of 13-14m with grating of 651 gr/mm15-20 minutes (S/N > 100)

Detector - CCD camera SPEC-10 (Roper Scientific, USA)

Readnoise1.50 ADU = 2.98 e-
Gain1.99 e-/ADU
QE95% Max. at λ5500 Å
Geometry1340×100 pixels, 20×20 μm
Well Depth262,000 e-
Dynamic resolution16 bits, 100 kHz
Coolingup to -100°C, regardless of ambient

Spectrograph ASP-14 in the coude focus

Characteristics of the spectrograph

Diffracting gratings600 Grooves/mm
Dispersion near Hα line2.4 Å/pixel
Spectral resolution with the entrance slit width of 0″.5R ≈ 30000

A detailed description of the spectrograph is to be found in the paper: Vasilyev, A.S., 1986, Bulletin of CrAO, V. 55, P. 224-235.

Spectrograph ASP-14 is not currently used.

Echelle spectrograph in the coude focus (ESPL) (Echelle Spectrograph Pronik Lagutin)

Characteristics of the spectrograph

Collimatorf = 6000 mm
Cameraf = 1080 mm
Echelle420×200 mm, 37.5 Grooves/mm, angle 63.5°
Grating150 Grooves/mm
Dispersion near Hα line1.39 Å/mm ≈ 0.019 Å /pixel
Spectral resolution with the entrance slit width of 0″.5R ≈ 51000
Scale1″ = 0.083 mm ≈ 6 pixel
Exposure for stars of 10m (slit width of 0″.5)30 minutes (S/N ≈ 50 near H? line)

Detector: CCD camera Andor iKon-L 936

QE98% Max. at λ5500 Å
Geometry2048×2048 pixels (27.6×27.6 mm), 13.5 μm
Well Depth100,000 e-
Dynamic resolution16 bits, 100 kHz
Coolingup to -100°C

CCD camera in the primary focus


Focusing deviceFLI DF-2
Filter wheelCFW with BVRI filters
Frame size1024×1024 pixels, 8′.4×8′.4
Pixel size24 microns, 0″.5/pixel
Achieving magnitude with a total exposure of about an hour (by summing several dozen frames)24m.5 (V band)

The telescope was developed at the Leningrad Optical and Mechanical Association (LOMO) in 1960. Intensive observations in the 60s allowed obtaining a number of pioneering results on the physics of different variable stars and galaxies, characteristic features of the structure and chemical composition of the stellar atmospheres.

The main results gained with the Shajn telescope in the previous years are as follows:

  • extended collection of the direct images of several dozen galaxies in 7-9 optical bandwidths and studies of star-formation processes based on this data (A.B. Severny, V.B. Nikonov, I.M. Kopylov, K.K. Chuvaev);
  • solving problem of the symbiotic stars within the evolutionary model of binary systems consisting of different mass components (A.A. Boyarchuk);
  • the first fast spectroscopy of the red dwarf flares and development of the chromospheric flare model (R.E. Gershberg);
  • systematic studies of the quiescent spectra of the red dwarfs which led to the preliminary estimates of their atmospheric parameters (N.I. Shakhovskaya);
  • discovery of helium enrichment in the atmospheres of hot stars on the main sequence (L.S. Lyubimkov);
  • revealing variability of the Virgo-A jet in optics and existence of strong stratification of the gas density in gaseous structures of the Seyfert galaxies (V.I. Pronik);
  • spectral monitoring of the active galactic nuclei for more than 30 years (K.K. Chuvaev, I.I. Pronik, V.I. Pronik, Yu.F. Malkov, S.G. Sergeev);
  • the first photoelectric measurements of the stellar magnetic fields (A.B. Severny, V.M. Kuvshinov, N.S. Nikulin);
  • discovery of lithium spots in the atmospheres of cool stars, correlation with stellar structure of the magnetic field (N.S. Polosukhina-Chuvaeva);
  • detection of rapid variability of the active galactic nuclei on the time scales from several days to weeks (I.I. Pronik);
  • deriving the most reliable estimates of the polarization degree of the red dwarf flare radiation (N.M. Shakhovskoy, Yu.S. Efimov);
  • discovery of new evidences for mixing matter in stars to the giant stage (I.S. Savanov, S.V. Berdyugina);
  • detection of excess sodium in the atmospheres of yellow supergiants (A.A. Boyarchuk, L.S. Lyubimkov);
  • rapid changes in radial velocity of some rare-earth lines in RoAp stars (I.S. Savanov, V.P. Malanushenko);
  • discovery of asymmetry in the winds of T Tauri stars caused by characteristics of the stellar magnetic fields (V.P. Grinin, P.P. Petrov);
  • unveiling prominence-like structures of T Tauri stars (P.P. Petrov);
  • detection of the circumstellar grain size growth during flares of RS CVn stars and some other stars (Yu.S. Efimov);
  • discovery of anti-correlation between the X-ray and H-alpha emission of Cygnus X-1 (A.E. Tarasov);
  • the first systematic study of chemical anomalies in the atmospheres of pulsating Delta Sct stars (L.S. Lyubimkov, T.M. Rachkovskaya);
  • detection of the short stage of the evolution of Be-phenomenon existence (A.E. Tarasov, S.L. Malchenko).

In cooperation with the Odessa State University there have been carried out pioneering works on polarimetry of cataclysmic variables AM Her, BY Cam, QQ Vul, MV Lyr; unprecedented UV Cet flares of the white dwarf in the AM Her system have been detected, circular polarization in the intermediate polar V405 Aqr has been first discovered (Yu. Efimov, N. Shakhovskoy, I. Andronov, S. Kolesnikov).

During 8 international campaigns on the comprehensive monitoring of flare activity of the red dwarf EV Lac the basic spectral observations have been performed at ZTSh. One of the important results - detection of splitting of the ionized helium line during the flare on 08/31/94, presumably due to the mass ejection (R. Gershberg, N. Shakhovskoy).

ZTSh was used in collaboration with other organizations in works on the lunar laser ranging (V.M. Mozhzherin and N.S. Chernykh) and tracking spacecrafts during their moving to the Moon, Venus and Mars to measure coordinates of spacecrafts needed for correcting their trajectory (P.P. Dobronravin, V.M. Mozhzherin, V.K. Prokofiev, N.S. Chernykh).