Question: John Henry Reynolds was a British astronomer who served as the president of the Royal Astronomical Society who frequently corresponded with American astronomer Edwin Hubble, developed a formula for measuring the surface brightness of what? 
Sentence (from "John Reynolds (astronomer)"): John Henry Reynolds (1874–1949) was a British astronomer who served as the president of the Royal Astronomical Society between 1935 and 1937 and is known for his work on the classification of stellar bodies.
Relevant evidence: Yes