Burlington free press. [volume] (Burlington, Vt.) 1827-1865, 1854-05-19
I he Solar Eclipse

! ne solar Eclipse.
The eclipse of the Sun which is to occur
on the Goth inst. will be one Of very in
tcrcstng character to those who live in this
vicinity. 10 help our readers more easily to
understand the conditions of it, we have pro-
vldcd an accurate cut to illustrate the article
which Prof, Thompson has oblisingly favored
us with.
We suppose that all know that to produce
any eclipse, however small, of the sun, the
sun moon and earth must be 50 nearly in n
line. the moon being between, that straight
line could be drawn from the eve Of the obscrv-
er through some par; OF both the moon and the
sunat the same time. lfthe place of the observ-
er on the earth and the position of the three
bodies be such, that a straight line from the
Observers eye, can go exactly, or very nearly,
through the centres of both sun and moon,
the eclipse will either he total or annular If
| then the distances of the earth moon and sun
| from each other are such in the case Just sup.
posed, that the conical shadow of the moon
reaches quite TO The earth where the observer
is, the eclipse will be total lit does not
reach the earth, as is more often the case, the
eclipse will be annular, as in the one on the
Goth inst. The figures will almost explain
themselves. The clear white circle represents
the sun, and the shaded circle, not quite so
large represents the apparent sire and posi-
ton of the moon az The moments when the
eclipse begins, at the middle of it, and at the
Il l..
the figure, will not be seen by the naked eye
at the beginning and end, but only the slight
apparent notch on the suns edge where the
two circles appeal to touch When the ring
is fully formed, the entire shape of the moon
will be seen on the suns disk as represented.
We hope for fair day when the eclipse
occurs, and that thousands will avail them
selves of the easy aid of well smoked glass,
if no better meane are within their reach, to
observe it with safety and satisfaction. 1t
will be an event worth remembering.
Such phenomena are not merely the occa
sion of high qualification when witnessed
They are of great scientific Importance -
From the careful noting OF the times and con.
ditions of their occurrence from age to age
have been derived much Of the means for de
terming the length of the solar year-the dis
lance and size Of the sun-the correct lonui
tude Of places on the earth---the position o
the carth's track through the heavens ant
many other things highly interesting and i'm
portant for man to know
Wonderful, as it may heem, that the begin
ming, end and magnitude of an eclipse, can b.
calculated so closely, it can not be as accu
rately done as it will be, ages hence, Tn
careful and exact observation oleverv new enc
with the best aids which the various observa
tories of the world can furnish, helps to deter
mine these coming afterwards more prccsel
than any We're determined before, and also t
give additional precision to the determination
of every great fact in the whole body @
astronomical science,
Without specifying all the details belonging
to a correct scientific observation of an eclipse
we will just remark that it depends essential
on two things, First that a tine-piece .
great accuracy should have been provided
and SO tested that the time by it may be re
lied upon to a small fraction of second -
Second that the precise instant when, by tn
aid of a good telescope, the circles Of the su
and moon seem to touch each other at til
, beginning of the eclipse, should be noted -
The same is done for the instant at the clos,
/ when they seem exactly to touch previous t
= their entire separation. Other particular
} are noted when they can be, but the era,
E times Of The contacts as they are called in col
/ nection with other known facts of the solu
system, furnish the basis Of the astronomer
f calculations,