Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1888-12-29
THE SUN ECLIPSE
WHICH il To TAKE PLACE NEXT
TUESDAY.
Directions by which Persons may
take Observations of the "Shad-
ow Bands" on that Day.

Professor Winslow Upton, of Providence
r. l., has issued the circular letter given
below, concerning the total eclipse of the
sun to occur January l, 1889, concerning
the taking of certain observations by any
person who will take the trouble to do so.
Professor Upton wishes to have as many
make the observations described as will do
50, and send report of the same to Sergeant
james A. Barwick, Signal Officer, Sacra-
mento, who will forward them to the au-
thor Of the letter following:
TOTAL ECLIPSE OF THE SUN, JAN. l, 1889.
One of the most peculiar appearances TT
tending total eclipse of the sun is that
generally known as the "Shadow Bands"
They are long dark bands, separated by
white spaces, which are seen on tie ground
or sides Of buildings just before and Just
after the total phase OF an eclipse, moving
rapidly. 1t is probable that they are not
real bands, but are composed of dark
patches which seem TO the eye to make
long bands. Their cause is not yet clearly
known, as the observations in former
eclipses are quite discordant. The under
signed IS very DESTROYS of obtaining obser-
yations Of them at various stations along
the line OF totality, especially at places
near the edge of the shadow, in order to
compare with similar observations made
by himself and others. The observations
require no special instruments and can be
made by any careful person. Information
. a fnIl ~
the direction in which the bands lie; ~
the direction in which they move; (3) the
velocity with which they move; (Gthe width
of tie bands and their distance apart. All
Of these are likely to be different before
and after the total phase, SO that two sets
of observations are needed. The following
suggestions are compiled from various
sources
Spread a white cloth or piece Of canvas
upon the ground in any convenient open
space. Il is well to spread two cloths or
pieces of canvas, one to be used before the
other after the total phase. Let each OBJ
server be furnished with several sticks four
TO six feet long.
About five minutes before the time of
totality, let the observer stand near the
cloth with his back to the sun and watch
the cloth intently. If bands or dark patches
are seen, place one stick down in the di-
rectIon in which they lie; after this is
done place a second stick in the direction
in which they are moving. Both of these
operations should be done deliberately, not
hurriedly, and the sticks lett in position.
Daring the total phase the observer is
free to enjoy the scene or make other OBJ
hut h. =
any bands can be seen during totality, as
some have asserted.
Al The close of totaIity the observer
should be at the second cloth. or at an
other part of the single cloth IF he uses
but one), and should repeat the observa-
tons made before toiality, placing one
stick down in the direction in which the
bands lie, and another III the direction in
which they move.
1t Will re seen that four sticks are needed
for these observations. Ii two persons
make the records, one should contine his
attention to the direction in which the
bands lie, the other to the direction in
which they move. The bands are likely
to be somewhat faint and poorly defined
so that extreme accuracy may not be pos
sible
Ths stick should not be disturbed until
alter tae eclipse. when their direction
should ne determined with as much care
As pu--iele, either by compass or still
better, by a surveyors theodolite, if one
is avsilahle If neither compass nor theo-
do'itr IS al hand, an estimate of the direc-
tions should be made
The velocity with which the bands
3 a Il. J
estimates vary from the speed OF man
running to that of an express train. Sew
eral methods may be suggested:
a. Let two persons work together, one
having watch with the seconds marked
on the face. Let him mark time bv cali
ing out each second. The number of the
second IS not important, but simple
sound TO mark the second, is sufficient.
Lei the other observer watch the band,
and see now many he can count per ,et-
ord
o. With one observer marking time a,
before, let the second observer note how
many seconds elapse while band IS PASS
ing between Two objects whose distance
apart is known.
(3.) lie; person run short distance
with the bands and see il he can keep I'D
with tnea. II not, let him estimate how
much fa-ter the bands are moving than he
can run.
"a = mere guess at the speed is OF some
value.
The width of the band, and their dis
lance apart Z; n bts. be determined upon
the cloths mentioned above and it will
add TO the accuracy of the estimates il the
cloths are divided by seams or in some
other way into strips of known width. A
carpenters rule will aid the observer in
making the estimates. The bands will
probably be several inches wide and sep
arated by spaces whose width is the same
or greater.
Ii the observer notices any other point
connected with the bands, such as color.
whether they are straight or wavy, whether
they are continuous bands or made up of
dark patches, whether they flicker or not,
the information will be valuable.
If, for any reason the observati, n
seems unsatisfactory, either because the
hands we're not as distinct as expected. or
for any other reason, or if the record is
only fragmentary, it will still be of value.
The report should consist of Statement of
the methods employed by the observer or
observers IN making the observations, and
the result obtained, with any remarks
upon the subject or upon other phenomena
noted al the time of the eclipse
WINsLow UPToN.
Providence, r. l., December 10, 1888.
The observations may be summarized as
follows
OBSERVATIONS OF SHADOW BANDS, JAN l, 1889.