On December 21, the inhabitants of the Earth could observe a rare astronomical phenomenon. In the evening sky, the two bright planets Jupiter and Saturn were visible at a small angular distance from each other, only 6 arc minutes. This is 5 times less than the angular diameter of the full moon and 2 times less than between the Mizar – Alcor binary system. It was very difficult for ordinary observers with the naked eye to distinguish two planets separately, as if they had merged into a single whole. Such close passages of the planets are called great conjunctions. The last time such a phenomenon occurred was in the spring of 1226.
On the Zeiss-600 telescope at Fesenkov astrophysical institute managed to photograph the great conjunction of these giant planets (lower photo). For comparison, here is a snapshot of a Russian cosmonaut Sergey Kud-Sverchkov (upper photo).