Evening star., 1901-09-07
POWER OF VENUS LIGHT
PHOTOGRAPHS MADE By RAYS FROM
THE BRIGHT PLANET.
Experiments by an AstrOnOmer-An-
cient Beliefs About the
Brilliant Star.
From the Centuu.

strange, fnOeeO, Dut IL IS al dCCohPhSHSu
fact. By this is not meant the photograph
ing of the image Of the planet itself
through the Intervention Of the telescope
or camera, but the use Of the simple, di-
rect rays from Venus, just as they come
from the planet. These direct rays, when
allowed to fall upon a sensitive plate, In
front Of and In contact with which mega
tive or positive. Photographic or otherwise.
is placed, are sufficiently actinic to repro
duce (naturally in reverse) the image or
such negative or positive. and with
wealth Of detail quite remarkable. My
pictures illustrate some Of the work done
in the manner described by the agency Of
the light from this most charming Of plan
/ cts
Queen Of beauty .
Star of the Evening, beautiful star.
These experiments were not, however, con-
Quoted when Venus was evening star,
but in its more recent phase as morning
star"
The ancients. by the way did not under
stand that Venus as our beautiful morning
and evening star was one and the same
planet. Its movements were great puzzle
to them. They called it Hesperus as even
ing star, and when on the other side Of the
sun they called it Phosphorus, Son of the
Morning. The wise Pythagoras, however.
perceived and taught that these two names
revolutions, Is appeared alternately upon
the eastern or western side Of our great
central luminary.
Venus as Morning Star.
Venus became morning star upon the Sth
Of July, 1900, and reached its greatest
elongation from the sun-about forty-six
degrees-on the 18th of September. It was
soon after this that the experiments herein
illustrated were begun, being some time
after the planet had reached its greatest
brilliancy. The remarkable success attend
ing the very first experiment was pleas
ant and gratifying surprise.
1t Is well known that objects placed in the
path Of the rays of light coming from
Venus when brightest will cast distinct
shadows. These are very sharp and well
defined when received upon white sur
face. The shadow of ones hand. for in
stance. even when held some distance from
white card or paper, Is remarkably dis
tinct In outline. This sharpness Of defini-
ton will be readily understood when we
remember that the light from Venus is
emanating from almost point as viewed
from the earth. so distant Is the planet.
My attention has often been attracted by
this in the dark dome of the observatory,
when the open shutter has been directed
toward Venus. On the western, inside wall
OF the observatory, and, of course, facing
the east, are a number of tables of stand
ard stars and prominent clusters and nebu-
lac. These are on white cardboard and as
passed and repassed them in my work a
perfect silhouette was cast upon these
cards. showing the distinctive brightness of
this far-away light.
Making a Test.
Was this light of sufficient actinic inten-
sity to affect the Photographic plate? The
thought rested with me for some time, and
at length decided to make the test.
A piece Of clear glass was placed in pho
tographic printing frame. on which was
laid piece of lace; on this in turn a gela-
tin dry plate was placed, and the back Of
the frame was closed, pressing all into con-
tact. In another frame plate was placed
In contact with a landscape negative. The
two plates were exposed side by side to the
rays Of light coming from Venus through
the open shutter of the observatory dome
All other light was carefully excluded ex-
cept that which came from the planet and
the exposure was made at the darkest hour
of the night after Venus had arisen, and
before the approach of dawn. The time of
exposure was about thirty-five minutes
Pictures were successfully made at the
next trial. two mornings later. Numerous
other pictures were made in much the same
way. In some cases the negative was made
from transparency. in others a positive
from negative solely by Venus-light This
positive was reproduced into a negative,
from which the prints were made by the
usual methods. The exposures were from
thirty to forty-five minutes, according to
the density of the negative and the clear
ness OF the sky. In all cases the plates
proved to be fully timed, the chemical ac-
ton being much stronger than was antict-
pated.
The light by which these experiments
were made proceeded first from the sun to
Venus, and was then reflected from Venus
to its neighboring planet, the earth How
lar had this light Travelled on It's great cir
cunt! One hundred and sixty millions of