The Worcester spy. [volume] (Worcester, Mass.) 1898-1904, 1901-11-16
CAMERA CAPTURES
COLOR OF LIGHT MING
First Successful Pictures Of the
Spectrum Of Lightning Have
Been Taken at the Harvard
Observatory New Field Open

Cambridge. Mass, Nov 16, 19O1.-The
first successful experiments in photo
graphing the spectrum of lightning
the divisions Of color which combine
TO produce the white glare of the light
ming flash and offer the physicist his
opportunity to analyze the elements
that compose it's announced in cir
cular sent out today by Professor 70. g.
Pickering, the director of the Harvard
Observatory.
The photographs were obtained at
the Observatory last summer with the
same apparatus that was used in pho
| tographing the spectra of the stars,
consisting of a big 8-inch or ll-inch
| telescope with a camera at one END
and a prism at the other, the latter be-
ing placed in front Of the objective lens
SO as to break up the object photo
| graphed into parallel bands of color,
which are seen in the photograph by
! differences in degree of black and
white. The effect will be familiar to
| anyone who recalls the colored border
produced by the pendant glass prisms
on old fashioned lamps Photographic
spectra, however, range only from yell
low to blue, the extreme colors, violet
at one end and red at the other, as
seen III the IdluDOW, MltlCli 10 Tic SpCt-
trum of the sun, being impossible to
record by the camera.
The scientific value of these spectra
arises from the fact that the various
elements of the atmosphere as well as
the various elements of solid bodies
under the influence Of the intense
heat, give off different colors, by which
they can be differentiated. The element
of hydrogen, which is found in the
spectra of nearly all stars, produces
a series of we'll marked lines quite diff
ferent from those made by the element
of iron, for example, found in some but
not all stellar spectra. The photo
graph of the star spectrum is not so
much a photograph of the star as of
the luminous vapor Immediately sur
rounding it, from which it is possible
to deduce the constitution of the burn
ing mass of the star itself
The successful photographic Of the !
spectrum of lightning is an achieve |
parative study. The photographs Sc
of them taken in July by !
Mr. j. H. Freese of Harvard, and one |
by the same observer in September
include several flashes and naturally |
suggested immediate comparison with |
the stars. These comparisons are given /
at length in Professor Pickering's cir
cular. Briefly 1t may be said that the |
hydrogen lines are found to be very
much like those shown by the spectra |
Of new" stars, such, for example, as
Nova Persei, the discovery Of which |
by the Edinburgh astronomer, DR.. An |
derson is still fresh in the public |
mind The chief difference is that the |
spectrum of Nova Persei shows dark |
lines, providing the presence of a solid |
body, while the lines of the spectrum |
Of lightning, which is simply flash in |
the sky, are all bright. Another inter-
esting comparison shows that the hy- |
drogen lines Of lightning flash that |
Illuminated the whole heavens cores
pond almost exactly with those of |
little quarter or an inch flash of light |
ming produced artificially in a small |
tube or in the open air.
Photographing star spectra is of |
nothing new at the Harvard |
where stellar photogra- |
ply has been more fully developed. |
than anywhere else, so that |
it may seen strange at first glance |
that the Harvard Photographic tele- !
scopes would not have been earlier |
utilized in the study Of lightning. The |
main difficulty lies in the fact that |
lightning is almost always aceompa-
MED by rain and that the rain inter- /
feres with the use of the telescope. |
Last summer, however, there were |
several Opportune dry Showers
Clouds and lightning without rama
condition which made It possible to