Orest Danilovich Khvolson or Chwolson (; - May 11, 1934) was a Russian and later Soviet physicist and honorary member of the Soviet Academy of Sciences (1920). He is most noted for being one of the first to study the astronomical gravitational lens effect.

Early life and education

Orest Danilovich Khvolson was born on 22 November (4 December, New Style) 1852 in Saint Petersburg, into

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