Obituary: The New Englander, No. XI, p. 40, July 1845; see also: J. Ashbrook, Sky & Telescope 12/1972, p. 366
Mason observed nebulae with a self-made reflector 12" reflector errected in 1838 at New Haven, Conn. The results are published in: Mason E. P., Smith H., Observations on nebulae with a fourteen feet reflector, Transactions of the American Philosophical Society 7, 165-213 (1841). It includes a fine drawing of the Trifid Nebula M 20.
Birthplace at Washington, Litchfield Co., Conn.
Mason's drawings (1839). Top left: M 17; Top right: M 20; Bottom left: Veil Nebula; Bottom right: John Herschel's drawing of the Vail nebula.