The so-called Kostinsky Effect involving the merging of closely occurring stars on a photographic plate is named after him as are an asteroid and a crater on the Moon.

He began to work on astrophotography under Oskar Backlund from 1895 producing gelatin glass images which were used for making accurate measurements.

He obtained remarkable images of the solar corona during an eclipse in 1896 observed from Novaya Zemlya.

He was also involved in accurate measurements of the arc of a meridian in 1899-1901 at Spitzbergen in collaboration with Swedish scientists.

[2] Kostinsky was also involved in training young astronomers and popularizing astronomy, teaching formally as a professor at the Petrograd University from 1919.