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
Lowell (Martian crater) then started observing Mars intensively for years. He used the observatory and his large refractor telescope to discover over 500 canals on Mars. Lowell promoted the idea that they were constructed by an intelligent race of Martians. However, when pictures were received from spacecraft, the canals were found to be optical illusions. Nevertheless, much of the later interest in Mars exploration resulted from the efforts of Lowell. Lowell (Martian crater) The Lowell Crater is a large impact crater on Aonia Terra in the Thaumasia quadrangle of Mars. The crater is about 203 kilometers (127 miles) in diameter. Lowell Crater has