VESTAL: Space Observatory

The VESTAԼ project was developed in the early 2000s at GIKA under the leadership of academician Grigor Gurzadyan.

The VESTAL space astrophysical observatory was designed to obtain information about the emissivity of celestial objects in the form of direct images and spectrograms in the far ultraviolet region – from 500 A to 100 A and shorter.

The working field of view of the VESTAL telescope is small – less than one minute of arc, and therefore it can be used to obtain direct images and record spectra of non-extended point objects. The choice of types of celestial bodies is determined by their expected or assumed activity in the region of wavelengths shorter than 500 A. This primarily applies to the following categories of objects:

• high temperature stars;
• X-ray sources;
• white dwarfs; symbiotic stars;
• cores of planetary nebulae;
• planetary nebulae;
• former cores of planetary nebulae;
• flaring stars;
• crowns of cold stars;
• objects of type RS CVn;
• quasars; active galaxies;
• Wolf-Rayet stars;
• former novae and supernovae.

The choice of specific objects of observation was determined by the requirement that they be sufficiently far from the galactic plane, when observations in the region of wavelengths near 500 A and shorter become possible due to the weakening of interstellar extinction.

The task is accomplished using three elements: a telescope, a camera, and a spectrograph or spectrographs. Both direct images of objects in the sky and their spectrograms are recorded by a CCD-based electron diffraction system with their subsequent transmission to Earth via radio telemetry communication channels.

Optical system of the VESTAL observatory
The VESTAL observatory was developed in two versions:

• Option A. Telescope – Parabolic hyperbolic Cassegrain oblique incidence
  Spectrograph – Oblique Incidence Rowland System
• Option B. Telescope – Parabolic Mersen oblique incidence
  Spectrographs – Wadsworth oblique incidence system

In both options A and B, optical systems of telescopes are offered for the first time and have not been used anywhere before.