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PUBLIC^DOMAIN^/^ COURTESY^ OF^ AUTHORtSPREADING LIGHT
Groundbreaking for the
Cincinnati Observatory took
place on November 9, 1843,
on the summit of Mount Ida,
soon to be renamed Mount
Adams in honor of John
Quincy Adams, who laid the
observatory’s cornerstone.
The land for the observatory,
which was on a south-facing
slope of the hill (marked with
a bold black circle on this c.
1900 map), was provided by
the Cincinnati banker and
speculator Nicholas Long-
worth. By the 1870s, light pol-
lution from the expanding city
forced the construction of a
new observatory on the top of
Mount Lookout (marked with
a bold black square).qLARGEST TELESCOPE
The Cincinnati Observatory’s
11-inch Merz and Mahler
refractor had a focal length
of 17 feet. It was the largest
telescope in the United States
when it saw fi rst light in
early April 1845, a distinction
held until the 15-inch Merz
and Mahler refractor was
mounted at Harvard College
Observatory in June 1847.skyandtelescope.com • NOVEMBER 2019 31qLARGEST TELESCOPE
The Cincinnati Observatory’s
11-inch Merz and Mahler
refractor had a focal length
of 17 feet. It was the largest
telescope in the United States
when it saw fi rst light in
early April 1845, a distinction
held until the 15-inch Merz
and Mahler refractor was
mounted at Harvard College
Observatory in June 1847.When Mitchel was 15, he happened across a notice stating
that qualifi ed young men could be appointed to attend the
U.S. Military Academy at West Point, New York, tuition-free
while receiving $28 per month. Founded in 1802, West Point
overhauled its curriculum in 1817 to become the United
States’ fi rst engineering school, modeled on the École Poly-
technique of France. Instead of a traditional college classical
education, cadets received a rigorous foundation in math-
ematics through calculus, and in civil engineering, learn-
ing how to design and construct bridges, railroads, canals,
arsenals, and fortifi cations. Summers were spent setting up
military camps and performing drills. Mitchel appealed to
Ohio politicians for letters of recommendation to support his
application. Early in 1825, he received his cadet’s warrant to
report for examination on June 1st.
In 1829, Mitchel graduated 15th out of a class of 46 (the
other 92 cadets who entered with him washed out). After a
summer working as an engineer for a railroad in Pennsylva-
nia, Mitchel taught mathematics at West Point for two years