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Published online by Cambridge University Press: 07 August 2017
The Zverev photographic vertical circle (PVC) of the Pulkovo observatory is in the process of modernization. The features of the vertical circle are:
a) Maksutov mirror-lens optical system with small aberrations and wide passband: aperture: 20 cm, focal length: 200 cm, focal scale: 103 arcsec/mm.
b) Very compact instrument: 140 cm total length, 60 cm — tube.
c) Wide field: 25 × 25 mm = 40′ × 40′. Wide-field imaging can be combined with meridian observations.
d) Easily-reversible instrument: reversing takes less than 30 seconds.
e) Two divided vertical circles of glass. Photoelectric circle reading microscopes.
f) Photographic micrometer in focal plane. This will be changed with a CCD micrometer.