Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1881-07-07
The Comet.


The big comet which made it, appearance
% suddenly . couple Of days ago was
watched and its position measured yester-
day morning through the big telescope ut
the Dearborn Observatory. The length Of
the comet and tail measured almost precise
ly eight and half degrees, with . few signs
of streamer light extending little further,
but not forming definite tail beyond the
limit named. Some of the published esti-
mates Of length, made by the parties who
first saw the comet, were much greater than
this. 1t appears probable that the tail was
really longer ON Wednesday morning than
yesterday; As it is 30 described by . gentle
man who saw it on both days. At twenty
four minutes past three O'Clock the declina-
ton was forty-six degrees forty EIGHT min
utes north, and the right ascension five
hours and thirty six minutes, within . few
seconds.
The comet IL travelling at the rate of about
five degrees northward, ~ minutes of time
eastward, per day. The angular diameter
the distance from its center to the apparent
top Of the envelope was 76 seconds of arc.
Day before yesterday 1t was . mere matter
OF guess that this newly discovered comet
was identical with the comet of 1872, which
was discovered by Pons in July, passed It's
by Encke to have q period of seventy and
seyen-tenths years, which would bring 1t
around again in the early part of 1888. IL 10
well-known fact, however, that the meas
ures Of position OF . comet, moving in q
very elongated orbit, can scarcely be
depended upon to give result much nearer
than this, especially il the perturbing xttrac-
lions of the planets of the solar system are
not taken into the account. The met of
lSl2, Tor instance, has swung out into space
q frAr h. sf.
greater than that Of the earth, which carried
1t considerably beyond the orbit Of Saturn,
and the attracting power Of the giant masses
OF the solar system, to say nothing of the
hundreds OF asteroids which have been dis
covered since Encke made his calculation,
are quite sufficient to cause such difference
in the result, IL the comet passed near some
of them.
Making due allowance for this, the motion
OF the comet, as so far observed, is partly
reconcilable with that of the comet Of 1872.
1t is travelling in, approximately, the same
plane, but the position OF the point OF peri
helion passage in the computed orbit does
not AZ pear TO agree with that Of the pres
ent comet. The measures taken yester-
day have been collated by the Tribune as
tronomer, and he has decided the follow
ing as approximate statements Of magni-
tude-in terms with which the average read
er is more familiar than with degrees and
minutes:
The distance Of the comet from the earth
yesterday morning was 10000, 900 miles; the
diameter of the nucleus, 1000 miles; the
shortest diameter Of the comet, measured
through the nucleus, $1,000 miles; and the
length Of the tail, 4,500,0O miles.
The comet would appear TO have already
sun; and the shortening of the tail, above
referred to, might be supposed TO indicate
that 1t has passed its perihelion some days
ago. The latter, however, does not rest on
sufficient data as yet. 1t is well known that
ut least three observations, at moderate in
tervals of time, must be made of q comet
before the elements of its orbit can be de-
termined by its computers. Hence other
observations, besides those made yesterday,
will be required to establish the leading
quired measures will be made at the Dear
born Observatory and at numerous other
places. weather permitting; and the comet
IL rapidly moving into a more favorable part
OF the heavens for measuring than that in
tho United States As above noted the
comet is rapidly moving northward. The
degrees Of yesterdays motion carried it SO
far north that it was above the horizon dur
ing the whole OF last night, instead of being
night. 1t will be above the horizon the
whole OF tomorrow night, passing the low
est point due north about twenty minutes
past eleven O'Clock, and will be visible, with
q clear sky, from dark till twenty minutes
past eleven to the west Of north, and from
twenty minutes past eleven till daylight to
the east OF north. just how long it will
continue visible cannot at present be told,
but it will undoubtedly be q brilliant object
in the evening sky for several days, and pos
sibly weeks, hence. The line of reasoning
adopted I'm regard to its present distance
leads, however, to the conclusion that il is
in brilliancy. 1
1t may be interesting to know that the
length of the tail yesterday morning was
four times the greatest observed length Of
tail carried by the comet OF 1872 That,
however, is no proof that the two are not
identical, as the apparent length Of tail de-
Ponds upon the distance from the sun when
seen, and also, to q very large extent, upon
its distance at the same time from the OBJ |
server, who watches ii from the surface Of
Ihe er-moving earth.-Chicago Tribune,