Percival Lowell detail in mid-1896 soon after the Alvan Clark & Sons refracting telescope was installed at his new Flagstaff, Arizona observatory. Lowell observed the planet high in the daytime sky with the telescope's lens stopped down to 3 inches in diameter to reduce the effect of the turbulent daytime atmosphere. Lowell observed spoke-like surface features including a central dark spot, contrary to what was suspected then (and known now): that Venus has no surface features visible from Earth, being covered in an atmosphere that is opaque. It has been noted in a 2003 "Journal for the History of Astronomy" paper and
Chamberlin Observatory the observatory is heavily affected by light pollution, which limits its use in scientific research. Chamberlin Observatory Chamberlin Observatory is an astronomical observatory owned and operated by the University of Denver. It is located in Denver, Colorado (US) in Observatory Park. It is named for Humphrey B. Chamberlin, a Denver real estate magnate who pledged $50,000 in 1888 to build and equip the facility. The observatory building was designed by Robert S. Roeschlaub, with the astronomical aspects and functions designed by Professor Herbert Alonzo Howe after he visited many observatories in the east. It was modeled after the Goodsell Observatory