Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists of the 20th century. Hubble is known for showing that the recessional velocity of a galaxy increases with its distance from the earth, implying the universe is expanding.

Wilhelmina Iwanowska (1905–1999), distinguished Polish astronomer, worked at the Vilnius (1927–1940) and Torun (1945–1999) universities and was the Vice President of the IAU from 1973 to 1979. She was the first Director of the Institute of Astronomy of the Copernicus University in Torun. Prof. Iwanowska was elected an Honorary Member of the Royal Astronomical Society of Canada on 1973-09-22, in the year of the 500th anniversary of the birth of Copernocis. Prof. Iwanowska had traveled and lectured extensively in Canada that year.

Named in memory of Kiyotsugu Hirayama (1874-1943), discoverer of the so-called Hirayama families of minor planets. Hirayama is also honored by a lunar crater.

Professor Hirayama, of the Astronomical Observatory, Tokyo, was elected a Corresponding Fellow of the Royal Astronomical Society of Canada on 1907-10-01.

Orbit type: Main Belt Asteroid 

Reference: M 4237

Sherburne Wesley Burnham (December 12, 1838 – March 11, 1921) was an American astronomer. His parents were Roswell O. and Marinda (née Foote) Burnham.

He worked at Yerkes Observatory. All his working life, he served during the day as a court reporter and was an amateur astronomer, except for four years as a full-time astronomer at Lick Observatory.

Herbert Hall Turner (13 August 1861, Leeds – 20 August 1930, Stockholm) was a British astronomer and seismologist.

Herbert Hall Turner was educated at Clifton College and Trinity College, Cambridge. In 1884 he accepted the post of Chief Assistant at Greenwich Observatory and stayed there for nine years. In 1893 he became Savilian Professor of Astronomy and Director of the Observatory at Oxford University, a post he held for 37 years until his sudden death in 1930.

Percival Lawrence Lowell (March 13, 1855 – November 12, 1916) was an American businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the effort that led to the discovery of Pluto fourteen years after his death. The choice of the name Pluto and its symbol were partly influenced by his initials PL.