The telescope (T-170M) consists of the optical system, structural module and service complex. The primary mirror unit (PMU) is the main structural element of the telescope.

There are three attachment points of the telescope to the spacecraft service module in the bottom frame part. The optical bench with scientific instrumentations devices and primary mirror baffle are mounted on the PMU frame. The secondary mirror unit (SMU), the light protective cover with the deployment mechanism and rotary external baffle with its fixing unit are located in the top part of telescope tube. The external rotary baffle has an oblique cut for light exposures prevention of the telescope internal cavity. It can be in two positions: transport and operational. The translation of the external baffle from the transport position to the operational one is carried out after spacecraft insertion onto the low Earth orbit (LEO) by turning it by 180 deg. The turning is performed by the actuators located on the top frame parts of the telescope.

   1. Primary Mirror
   2. Mechanical frame
   3. Primary Mirror Unit basic frame
   4. Radiator with heating elements
   5. Tube
   6. Secondary Mirror Unit
   7. External Baffle
   8. Telescope Light Protective Cover
   9. Primary Mirror Baffle
10. Secondary Mirror Baffle
11. Ring knifes
12. Optical Bench
13. Focal Camera Unit
14. Spectrographs
15. External Electronic box
16. Scientific instruments protective cover

Optical System	Ritchey-Chrétien
Aperture diameter	1.7 m
Focal length	17 m (primary mirror)
f/#	10.0
Field of View (FoV)	30 arcmin (150 mm in diameter)
Wavelength range	110-850 nm
Primary Wavelength	200 nm
Optical quality	λ/30 rms at 633 nm (primary and secondary mirrors) Diffraction limited at FoV center
Angular resolution on focal plane	12.13 arcsec/mm
Mass	1570 kg (1600 kg with adapter truss)
Size	5.67 x 2.30 m (transport)8.43 x 2.3 m (operational)

The telescope is under development by the Lavochkin Association (Russia). The main units of the structural model of the T-170 prototype telescope have successfully passed vibrostatic and thermal vacuum tests. The primary mirror and other optical elements is being manufactured by the Lytkarino Optical Glass Factory (Russia).The T-170M telescope has assimilated the successful experience gained during the fulfillment of the "Astron" project.

Primary Mirror

The T-170M telescope is based on the classic Ritchey-Chretien scheme. The main parameters of the telescope are the following

Primary mirror diameter	170 cm
Focal length	1700 cm
Field of view	30 arcmin
Image quality	diffraction limited at the center of the field of view