Kostinsky Sergey Konstantinovich 
(31.07(12.08).1867–22.08.1936)

Soviet astronomer, corresponding member of the Academy of Sciences of the USSR, founder of Russian astrophotography. 
Born in Moscow. In 1890 he graduated from Moscow University, from 1894 until the end of his life he worked at the Pulkovo Observatory. In the 1920s he was also a professor at Leningrad University. 
In the first years of his work at Pulkovo, Kostinsky investigated changes in astronomical latitudes; He proposed a method for calculating the curve of motion of the pole, which was universally recognized. He was one of the founders of astrophotography and photographic astrometry, gathered a huge collection of photographs of the sky, including photographs of individual sections of the sky, which formed the basis of the so-called Pulkovo Glass Library. Comparing them with photographs obtained at the Pulkovo Observatory later allowed us to compile a catalog of proper motions of 18 thousand stars. Kostinsky elaborated a method for measuring the position of stars using photographic plates and derived formulas for the reductions of these measurements. 
In 1906 Kostinsky discovered the phenomenon of interaction between two neighboring images on a plate of close binary stars (Kostinsky phenomenon). One of the directions of his scientific activity was the study of latitude variability; he derived a formula for determining the coordinates of the Earth's poles on the variability of latitude observatories. 
Kostinsky participated in a number of expeditions, including in 1896 to Novaya Zemlya to observe a total solar eclipse and in 1899–1901. on Svalbard to measure the arc of the earth meridian. 
He died in Pulkovo, buried in the cemetery of the Pulkovo Observatory. 
Mountain on the island of West Svalbard. Named in 1899-1901  expedition on "degree measurement".