Front:
MEEEN
AVA
Back:
ADLER PLANETARIUM AND
ASTRONOMICAL MUSEUM
South Park Commissioners
Chicago, Illinois
The Planetarium instrument is exceedingly
complex, both optically and mechanically.
This is necessarily so for it depicts the entire
sky on the interior of the linen-lined dome
which forms the ceiling of the auditorium,
every star in its place and of proper brightness
and the Sun, Moon, and planets in their cor-
rect positions. It reproduces accurately the
changes due to the passage of time or change
of position on the Earth. Daily motions,
annual motions, or the great precessional cycle
can be compressed into a few minutes or even
seconds. It shows every astronomical phe-
nomenon that can be observed without a
telescope. To accomplish this there are 122
different projectors and seven motors which
may be combined in many different ways-
and all under the instant control of the
demonstrator.
HERE
