Evening star. [volume] (Washington, D.C.) 1854-1972, 1908-06-29
IS PICTURED
Photographs of Yesterdays
Celestial Mystery.
HALF TWILIGHT PREVAILED
Event Occurs Ten Seconds Ahead of
Schedule.
OBSERVATIONS ARE SUCCESS
Planet Venus Visible on Unob-
scured Part of Suns Face-Four
Planets in Proximity.

There was twilight effect at midday in
Washington yesterday. 1t came as a
result of the partial eclipse of the sun.
Thousands of Washingtonians. provided
with smoked glass. green glass. blue
glass and red glass, gaZed sunward-moOn-
ward at the interesting sky spectacle.
AS the orb of day and the orb of night
came into juxtaposition near the meridian
sort of softened twilight effect crept
over the city, awesome because of it's
strangeness. The point of greatest OBJ
servation was reached a few minutes
| before IL o'clock, when the churches
were in session.
The midday twilight gave the twitter-
ing sparrows and other members of the
feathered tribes a strong inclination to
go to roost For while there was a
sort of gloominess produced by the cloudy
weather effect from a clear sky. In all
parts of the District people gathered in
the open and studied the phenomenon
through darkened glasses.
observations Successful.
The eclipse was success from an
astronomical standpoint. The passage of
the moons shadow across the suns disc
occupied hours. Ii minutes and "a sec
minutes and g seconds past O'Clock.
The halfway point of the eclipse was
reached at IL o'clock. II minutes and IL
Sc conds. The last contact, as the shadow
passed clear of the suns brilliant face
was % minutes and . seconds past L:
o'clock pm.
Preceding the eclipse there was much
activity yesterday morning among the
astronomers and their assistants at the
Naval Observatory. Capt. W. ]. Bar
r rtnfn Of in
stitution, had arranged for the taking of
celestial photographs of the eclipse at
different stages. copies of which, through
the courtesy of Capt. Barnette, were
furnished the press.
The staff of observers was in imme-
diate charge Of Prof. W. S. Eichelberger,
an astronomer of note. Five observers
noted the time of contact. They were
tronomers G. A. Hill. j. c. Hammond,
Matt Frederickson, c. W. Frederick. A
photograph of the maximum eclipse was
taken by Assistant George II. Peters.
1t was explained that the eclipse ar
rived ten seconds ahead of the scheduled
! time, and lasted thirteen seconds less
than the predicted time.
Taking of Photographs.
The photographs of the moon in the
embrace of the sun were taken with a
photo-heliograph. forty feet in length All
equatorial telescopes. The day was fine
| for observations. The image of the sun
| was steady at the first contact, but
| somewhat less steady at the last.
| Prof. Eichelberger explained that the
phOto-heliograph is a Photographic cam
era, forty feet long. mounted horizon
| tally. Within two feet of the front end
of the forty-foot tube Tor bellows. to Dor
row a photographed termD is the tele-
scope lens. Two feet in front of it is a
wedge-shaped piece of unsilvered glass
called the mirror.
rect. diverts the major porto Of the
| light, and reflects the small Iainder
| upon the lens, which in turn i'm nts the
| image upon the sensitive plate at the
near end of the tube.
| This near end-earth end. it ight be
| cafed-is inserted in one We" of a
| square. dark room, within " lich the
| photographer stands. A vertical slit, one
sixteenth of an inch wide. ~ the near
| end of the tube, admits tbs light from
| the lens.
| At the precise moment Fle photOgra-
| pher. by quick. strong pull on lever.
| shoots the sensitive plate across this
! slit, thereby accomplishing an Exposure
| of about one one-hund: edith of a second
in duration. In thaI infinitesmal frac-
| ton of time the ct,ired image Of the
| eclipse is-and yes t@rday was-imprinted
upon the Photographer plate.
In total &c JSe, account of the
complete obscgi -ition of the luminary by
| the moon. tirne exposure of about two
| minutes is r~Iuired. and to achieve this
| a clock mechanism turns the camera tube
SO to keep the heavenly object always
| centered on the lens.
Ocular Principal Demonstrated.
| The diameter of the sun is S0O,OO0 miles.
| The diameter of the moon is 1000 miles.
But the sun is 92.JOOOOO miles away
| from the earth and the moon is only $1,000
miles away. So. upon the ocular princi-
! pie that the nearer an object is the bigger
| it looks. the moon. when it passed be-
! tween the sun and the earth yesterday,
| had an apparent diameter almost as great
| as the actual diameter of the sun. That
is why. when there is total eclipse. the
moon is big enough, looked at from the
earth. to all but completely hide the sun,
though the sun is 3O0 times as large as
the moon. Otherwise there could be no
| such "a thing as a total eclipse
| The seven photographs taken at the
| Naval Observatory yesterday showed. in
| addition to the moon projected upon the
sun, three fairly large sun-spot groups.