Born Moscow, Russia, 13 July 1854
Died Pulkovo, (Russia), 16 May 1934
Aristarkh Belopolsky was a pioneer in the application of spectroscopy, and especially radial velocity measurements, to the study of the stars. Belopolsky’s father was a well-educated teacher whose ancestors had immigrated to Russia from the Serbian town of Belopolje, from which the family’s name was derived. After an excellent secondary education, Belopolsky studied at Moscow University and graduated in 1877. During his studies, he came under the tutelage of Fedor Bredikhin , director of the Moscow Observatory. On account of Belopolsky’s mental vigor and technical skills, Bredikhin appointed him as an assistant at the observatory and encouraged him to participate in its solar observations. In 1886, Belopolsky completed his Magister’s thesis on the motions of sunspots. He then obtained several photographs of the corona during the total solar eclipse of 19 August 1887 near Pogoste (approximately 100 miles northeast of Moscow).
Belopolsky’s talents eventually attracted the attention of Otto Wilhelm Struve , who invited him to join the staff of the Pulkovo Observatory in 1888. Three years later, Bredikhin succeeded Struve as Pulkovo’s director and placed his former student in charge of all astrophysical equipment. Belopolsky was directed to purchase a standard Carte du Ciel astrograph and several stellar spectrographs. In 1891, he journeyed to Potsdam, where, along with American astronomer Edwin Frost , he learned the techniques of radial velocity measurements from spectroscopist Hermann Vogel .
Armed with new spectroscopic equipment and fresh ideas, Belopolsky set to work on the new field of observational astrophysics. Independently of James Keeler , he demonstrated the differential rotation of Saturn’s rings (1895). In 1894, he discovered periodic changes in the radial velocity of δ Cephei, and noted the phase shift between its brightness variations and the Doppler oscillations. Continued studies of this star netted Belopolsky his Ph.D. in 1896, from which the first hypotheses of stellar radial pulsations originated. Belopolsky likewise reported analogous behavior for η Aquilae (1896) and ζ Geminorum (1899). In 1906, he announced the long-period oscillation in the radial velocities of Algol (β Persei), thereby confirming the eclipsing binary hypothesis of John Goodricke and Edward Pigott .
Equally important were Belopolsky’s contributions to the study of novae. Beginning with the appearance of Nova Aurigae (1892) through Nova Aquilae (1918), he observed each one, often catching them in their earliest pure-absorption stage. It was perhaps consideration of the expansion of novae that led him to think of expansion as an important phenomenon in general, an attitude that appears to have influenced Victor Ambartsumian .
Belopolsky maintained an interest in solar studies throughout the remainder of his career, measuring the effective temperature of sunspots, timing the Sun’s rotation from the motion of faculae, and securing a large solar spectrograph of the Littrow type from Sir Howard Grubb .
In 1902, Belopolsky was appointed to the editorial board of the Astrophysical Journal, and the following year was elected a member of the Russian Academy of Sciences. He became an associate member of the Royal Astronomical Society in 1910. From 1917 to 1919, he served as director of the Pulkovo Observatory, but then resigned his position due to the impact of administrative duties on his research activities.
Of Belopolsky, his colleague Boris Gerasimovich wrote: “His most striking qualities were modesty, moral courage, clear vision and enormous devotion to science and industry. In the terrible years of the civil war, this old man, cold and hungry, continued his work as usual – an example of true heroism.”
Belopolsky was named honorary director of the Pulkovo Observatory in 1931 and continued his research on stellar spectra until his death.