Evening star., 1937-02-21
EPOCHAL ECLIPSE
COMING IN June
Geographic Society and
Navy to Sponsor 0bserva-
tions From Pacific Isles.

One of the longest total eclipSes Of
the sun In history will be observed
next June by a group of astronomers
sent out jointly by the National Geo
graphic Society and the United States
Navy, it was announced yesterday by
DR.. Gilbert Grosvenor, president of
the National Geographic Society.
The eclipse will be observed from one
Of the Phoenix Islands, group OF
tiny, barren coral atolls in the Pa
cific. On two Of these islands, the
period of totality will be more than
four minutes. Recent solar eclipses, to
study which expeditions have been
sent around the world, have lasted
less than minute. This Is the longest
for 1900 years. Its maximum du-
ration will be seven minutes and four
seconds, but at this point in the mid
Pacific there Is no land for 1000
miles.
Its path extends for more than
5000 miles across the Pacific. 1t will
be visible from the mainland Of Peru
about sunset, but then the sun will
be too low in the sky to permit satis-
factory observations
Will Cross Date Line.
A paradox Of this eclipse is that it
will lend the day before 1t starts"
according to Dr. Grosvenor's an
nouncement. It's path will cross the
international date line in the mid
Pacific, so that it will begin on June
and end on June 8.
Admiral William D. Leahy, chief OF
naval operations, has arranged for
the mine sweeper Avocet to transport
the party from Honolulu to the
Phoenix Islands early in May. The
scientific program is being directed by
DR.. Lyman j. Briggs, director OF the
Bureau of Standards, and chairman
of the National Geographic Society's
research committee.
The leader of the scientific stan
will be DR.. S. A. Mitchell, director OF
the Leander Mccormick Observatory
of the University of Virginia. Capt.
j. F. Hellweg, superintendent OF the
Naval Observatory, will be in charge
of the Navy party.
Among the scientists who will take
part in the expedition are DR.. Paul A.
McNally, director of the Georgetown
College Observatory; DR.. Heber D.
Curtis, director of the University OF
Michigan Observatory; DR.. Floyd K.
Richtmyer of Cornell Observatory;
DR.. Irvine C. Gardner Of the Bureau
of Standards, and John w. Willis OF
the Naval Observatory.
The expedition will establish itself
on either Canton or Enderbury Island,
both just south Of the equator, about
1900 miles southwest of Hawaii and
5000 miles northeast of Australia. The
islands are about 80 miles apart. The
one on which living and observing con-
ditions are found to be best will be
chosen. Both islands will be difficult
to land on. The Phoenix Islands. pos
sessions of Great Britain, are without
inhabitants.
Enderbury Island is about pa miles
long and l mile wide. while Canton
Island is approximately 8 miles long
and miles wide. Both have salt
water lagoons in their centers. At
Enderbury the duration of the eclipse
will be minutes and seconds
The scientific program, according
to the National Geographic Society
announcement. will be the most COM
prehensive ever carried out by eclipse
observers. Special attention will be
given to observation Of the suns
corona, visible only during q total
eclipse, and the chromosphere. or
outer layer of the sun, by photo
graphing the flash spectrum which
permits the determination Of the
heights to which vapors rise above
the suns surface
Flash Spectrum Fleeting.
This fash spectrum becomes visible
during the few seconds just after
the moons disk completely eclipses
the sun and Immediately before the
sun begins to emerge from behind the
moon. Dr. McNally will photograph
the corona with light of different
colors by using various types Of filters.
DR.. Richtmyer will measure the total
light of the corona.
DR.. Gardner will take with him the
same eclipse camera of his own de-
sign which he took to Russia for
last years total eclipse and with which
he obtained very successful photo
graphs. He also will take photographs
in color. The Naval Observatory party
will be especially interested in de-
termining the precise times the eclipse
begins and ends. This will serve
as an important check on calculations
Of the movements Of heavenly bodies
in which the observatory is chiefly
interested.
The great bugbear Of eclipse ex-
petitions, bad weather, is largely
absent in this case since weather
records from the Phoenix Islands show