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THE MICHIGAN QUARTERLY REVIEW
ordinary street lamps or lights in the nearby
dormitories and the University Hospital do
not directly injure the photographs at all,
for they do not shine into the spectrograph
slit, unless the light is diffused by haze or
smoke right in front of the telescope. Even
if such light does enter the spectrograph, it
is spread so thinly (because it is composed
of all wave-lengths) that its effect would be
negligible. Where the lights do make trouble
is in shining through the open shutters and
reflecting off the inside of the dome, thereby
making it difficult to see a faint star on the
spectrograph slit. When Alice Lloyd Hall
was very new, in 1949, extremely brilliant
lights were installed in the loading dock area
between the Observatory and the dormitory.
A newly added staff member remarked that
this was the only floodlighted observatory
he had ever heard of. We never knew whose
idea the brilliant lights were, but we surmised that the Dean of Women might have
had a hand in it. They were soon replaced
with bulbs that gave adequate illumination
without blinding the astronomers. But before
the change was made, one foggy night an
airplane flew very low over the area twice,
several minutes apart. Whether correctly or
not, we surmised that the pilot was lost and
mistook the brilliantly lighted area for Willow Run Airport.
The lights that really are a nuisance in
the actual photographs are the neon and
mercury lights that are now so common. If
we work in the red spectrum, neon light
scattered by the atmosphere can shine right
into the slit and record on our spectrograms
as bright lines piled on top of the star spectrum. Of course we know where these lines
are, but they may blend with lines of
the star spectrum and hamper our study.
Mercury gives two very strong lines in the
blue and violet. There are numerous mercury lights at Arborland shopping center, so
when we observe a star in the southeast we
often get strong mercury lines on our spectra, especially if there is smoke or thin haze
to scatter the light. A few years ago Saint
Joseph's Hospital installed a blue mercury
sign on its roof, so we get mercury lines
whenever we work in the northwest.
A MAJOR NUISANCE Of much longer standing has been smoke. For only a little
over three years after its completion, the
37-inch was free from interference. In 1914
the University power plant was erected in
the "Cat-Hole" about midway between the
main campus and the Observatory. The site
was one recommended by Mortimer E. Cooley, then Dean of the College of Engineering, and was approved by the Regents, over
the protests of the Director of the Observatory. From October 30, 1914, on, we find
frequent entries in the observing records
concerning smoke trouble. At first the source
of disturbance was plainly spelled out, but
later we find only the cryptic entry "PPS"
(for "power-plant smoke"). Since the most
frequent wind direction is from the southwest, and since the power plant is directly
southwest of the Observatory, the smoke is
more than just an occasional nuisance.
Heber D. Curtis (Director from 1930 to
1942) remarked that "When they selected
that site for the power plant they must have
made a careful study of the weather records!"
During the past few years another term
has crept into the records. It dates from the
time when plans for the Cooley Memorial
on the North Campus were announced. One
of our staff members, who has since been
lured away to clearer skies and larger instruments, remarked that: "We already have
a Cooley Memorial," the while waving his
hand toward the smokestacks. The name
stuck, and "Cooley Memorial" will be the
unofficial name of the power plant for some
of us as long as "PPS" plagues the observing. However irreverent it may seem, the
term "Cooley smoke" now appears in the
observing records and honi soit qui mal y
pense.
One of our graduate students claims that
the behavior of the smoke is the best known
example of "Gumperson's law." This law
has been variously stated, but it can be
summed up in the statement that things
conspire to make life as difficult as possible.
In the case of smoke versus astronomers,
this takes the form of the following sequence
of events. The smoke is crossing the north
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