Sky and Telescope - June 2018 - 40
George Ellery Hale
dedication ceremony. The Hale Telescope
saw ﬁrst light in January 1949, and Edwin
Hubble was the ﬁrst astronomer to use it.
With four times the light-gathering power
of the Hooker, it remained the largest
telescope in the world until 1975, when
the Russian BTA-6 telescope (238 inches,
or 6 meters) saw ﬁrst light. Because the
BTA-6 suffered from several design problems, however, many astronomers extend
the Hale record to 1993 when the Keck
Telescope began operation.
Time ultimately caught up with the
telescopes at Williams Bay and Mount
Wilson. The 40-inch refractor at Yerkes
Observatory transitioned to a teaching
tool after 1990; the observatory is scheduled to close permanently in October 2018. The last research
project on the 60-inch Mount Wilson telescope ended in
the mid-1990s. Although the Hooker Telescope was retired
in 2015, Mount Wilson Observatory celebrated the famous
reﬂector on November 1, 2017, the date of its centennial.
Viewing opportunities through both telescopes on Mount
t MR. MONEYBAGS Andrew Carnegie's money
played a pivotal role in the construction of Mount
Wilson, funding the construction of Hale's dreams
via the Carnegie Institution of Washington. This
photo shows Hale and Carnegie in front of the
steel dome of the 60-inch telescope, c. 1910.
Wilson are now available to the public
(S&T: Sept. 2016, p. 22).
Of all Hale's telescopes, only the 200inch reﬂector is still used for research.
Mansi Kasliwal has been working with
it since she was a student at Caltech.
"When you enter the main dome for the
ﬁrst time," she says, "you feel a part of
something much bigger. You get a feeling
of awe and inspiration and history that
really leaves an impression. If you're a young student, it can
change your life."
¢ STEVE MURRAY is a freelance science and technology
writer who stargazes from his home in San Diego, California.
He'll travel anywhere to explore new observatories.
All of Hale's telescopes are open for
public visits at present. With the exception of the Hale reflector on Mount
Wilson (still used for research), the
observatories offer opportunities to
stargaze through them, too.
Yerkes Observatory (https://
is.gd/yerkes): The University of Chicago recently announced plans to close
Yerkes Observatory. In the meantime,
scheduled public tours are offered
Monday-Saturday and are the only
way to see the building interior and
the 40-inch refractor. There's a nominal
charge for the tour. Private group tours
can be arranged on request. Because of
its dated architecture, the building isn't
Public observing with the 40-inch
refractor and 24-inch reflector (used by
George Ritchey to test his design concepts) is offered monthly at selected
times, weather permitting.
This Memorial Day weekend, Yerkes
Observatory will host Starlight 2018,
J U N E 2 018 * SK Y & TELESCOPE
an event tied to Hale's 150th birthday.
Speakers from Mount Wilson, Palomar,
and Caltech have been invited to participate in the free event.
Mount Wilson Observatory
are open daily, weather permitting.
Two-hour docent-led tours are offered on weekends between April 1st
and November 30th, with one-hour
tours added between June and August.
Private group tours are available with
advance registration. There's a nominal
charge for the tour. Visitors are free to
take a self-guided tour with downloadable guide. Distances and hilly terrain
limit access for individuals with health
or mobility concerns.
In keeping with Mount Wilson's
history of solar astronomy, free solar
viewing is available to the public on
The famous 60-inch and 100-inch
telescopes can be rented by groups for
half- or full-night viewing sessions. The
observatory also sets aside a number of
ticketed evenings throughout the year
for stargazing by individuals.
In honor of Hale's 150th birthday,
Mount Wilson Observatory has planned
a range of celebrations, beginning in
May. Events include a photographic
retrospective, a lecture series, a concert
series in the 100-inch dome, and weekend open house activities with free
nighttime observing (July or August).
Palomar Observatory (https://
is.gd/palomar): Observatory grounds
are open to the public daily, weather
permitting, except December 24-25
and during some maintenance operations. Visitors can tour public areas on
their own or participate in one-hour
guided tours of the Hale Telescope on
weekends, spring through fall. There's
a nominal charge for tours, but they're
free for youth and student groups.
Some areas - including the Hale Telescope dome - are not accessible to
UNIV ERSIT Y OF CHICAGO / Y ERK ES OBSERVATORY
George Hale's Telescopes Today