In 1887, Italian astronomer Giovanni Schiaparelli observed and sketched dark linear features on the surface of Mars – ironically, just as his eyesight had begun to fail. He called the markings “canali,” which can be translated as either “channels” or “canals” – therefore igniting the debate over whether the markings were natural formations or artificial constructions.

American astronomer Percival Lowell took up the Martian quest in 1894, firmly believing the lines were canals built by intelligent beings to transport water from polar ice caps in a desperate attempt to save their dying planet.

Obsessed with finding the perfect site for his observatory, he sent Harvard astronomers A.E. Douglass and W.H. Pickering to the Arizona Territory to search for a place where the air was clear and calm, creating minimal atmospheric interference while observing the skies.

While scouting for the best location, Douglas and Pickering invented the “scale of seeing” in which observing conditions were rated from zero, the worst, to ten, the best. The best possible viewing,a ten, was rarely experienced on Mars Hill, although the elevated mesa saw its fair share of sevens, eights and an occasional nine. 

In his dogged attempts to clarify the view through his telescope, Lowell often employed unusual techniques, including stopping down the aperture on his telescope (in effect creating a giant ophthalmascope). Some have suggested that the resulting narrow and intense beam of light reflected Lowell's own eyeballs and the “canals” he saw on Mars were in fact the network of veins inside his eyes. 

When other astronomers disputed his findings, he enlisted his associates on Mars Hill to verify what he saw. Miss Leonard was certainly one of those he expected to see the planet just as he did. But whether her drawings reflected what she actually saw may have been colored by his need for agreement and her dependence on him for financial and romantic fulfillment.