Our Telescopes

 2-m Ritchey-Chretien-Coude telescope 

The main instrument of the Terskol Observatory is a 2-m Ritchey-Chretien-Coude telescope. It is the fifth telescope of this size manufactured by Carl Zeiss Jena GmbH. It was put into operation in 1995. The focal length of the main hyperbolic mirror is 5.6 m. The equivalent focal lengths of the Ritchey-Chretien and Coude systems are 16 m and 72 m, respectively. The corresponding fields of view are 108 arcmin and 5 arcmin.

The 2-m Ritchey-Chretien-Coude telescope 

The photometric complex of the 2-m telescope includes a two-channel high-speed photometer with cooled photo-multipliers, UBVRI filters and a CCD guiding system. This complex has a precise timing and synchronization system based on the GPS smart antenna Acutime-2000. The accuracy of the timing and synchronization is better than l ms.

The additional instrumentation of the telescope consists of high-efficiency CCD cameras, spectrographs and some specific photometers.

 In 2008, the original control system of the telescope, VILATI, was replaced by a new one based on industrial automation tools. This system was installed by ProjectSoft HK a.s. (Czech Republic).

The 2-m telescope remains the main instrument of the Terskol Observatory and continues to make a valuable contribution to studying the Universe.


Solar telescopes 

During 1986–1992, absolute measurements of the solar disk-centre intensity were performed at Terskol. The observations were carried out using the instrumentation adapted for quasi-simultaneous registration of the solar and standard ribbon tungsten lamp spectra (Burlov-Vasiljev et al. 1995, 1998). The following facilities installed at Terskol were involved:

• grating spectrophotometer with collimator (D = 180 mm, f = 2 m), camera mirror (D = 230 mm, f = 2 m), and grating (140 × 150 mm, 600 or 1200 grooves/mm) mounted in the vertical plane,
• absolute calibration system, which uses a ribbon tungsten lamp placed at the focus of the collimating mirror (D = 230 mm, f = 3 m),
• atmosphere halo photometer used for monitoring of the optical properties of the Earth's atmosphere,
• auxiliary equipment to control the apparatus includes optical and electronical stuff for lamp feeding and control, for the investigations of the polarization properties of the coelostat group and spectrograph, for the measurements of spectral reflectivity of the lamp's collimator, etc.
• solar horizontal telescope with coelostat group (main mirror D = 230 mm, f = 3 m). 

As a result, the absolute spectral energy distribution was measured for the spectral interval 305 nm - 1070 nm. Moreover, it was shown that the calibration for the ground-based measurements can be fulfilled much more precisely and reliably than for the space-based ones (Burlov-Vasiljev et al. 1997).

The measured spectral (continuum + lines) intensity of the solar disk-center radiation in 1012 W•m-3•ster-1 (Burlov-Vasiljev et al. 1997) 

In 1992, the large horizontal solar telescope, ACU-26, built by the Optical-Mechanical Corporation LOMO (Russia), was put into operation.

The diameter of the main spherical mirror is 650 mm; its focal length is 17.75 m. The telescope is equipped with a 5-camera Ebert-Fastie spectrograph

The scheme of the large horizontal solar telescope ACU-26 The diameter of the spectrograph’s collimator and mirrors is 300 mm; the focal length of the collimator and mirrors is 8 m. The grating size is 250 x 200 mm with 600 l mm-1. The dispersions in the fourth order are 21.9 mm/nm at 395.0 nm and 33.0 mm/nm at 650.0 nm. The typical instrumental profile of the spectrograph has a FWHM of 0.0018 nm.

The telescope is useable to perform observations of selected regions or active areas on the Sun simultaneously in five wavelength ranges.

The Zeiss-600 telescope 

 The 60-cm Cassegrain telescope (Zeiss-600) has been in operation since the mid-1970s (Fig. 6). Its focal length is 7.5 m. Depending on the CCD camera attached the field of view is 9 x 8 or 4 x 3 arcmin. This telescope is currently used for astrometric observations with timing better than 1 ms, as well as for photometric observations with B, V, G, I or R filters. Observational programmes are aimed at obtaining precise data sets to study variable stars and asteroids.

The Zeiss-600 telescope 

Other telescopes and tools 

Included among the telescopes installed at the Terskol Observatory are a Celestron 11”, a Meade 14”, and an 80-cm telescope. But we still need to do some more work to start comprehensive scientific programmes with these telescopes.

During the last decade, the infrastructure to support observational activities at Terskol has been updated considerably. For instance, a DIRECWAY TM system is now used for Internet connectivity via satellite through a satellite antenna. Furthermore, to provide a proper maintenance of the astronomical instruments, a liquid nitrogen generator and turbo-molecular pumps are available on Terskol Peak.