The times. [volume] (Washington [D.C.]) 1897-1901, 1900-08-05

brilliant object was found in the constelIa-
tion Cassiopeia. 1t is known as Tycho's
star, since it Was the means of winning for
astronomy man who Will always take
high rank in her annals, Tycho Brahe of
Denmark. When he first saw this star. it
was already very bright, equaling even
Venus at her best; and he continued a
careful series of observations for sixteen
months, when 1t faded finally from his
view. The position of the new star was
measured with reference TO other stars in
the constellation Cassiopela, and the re-
suits OF Tycho's observations were finally
published by him in the year 1873. 1t sp-
pears that much urging on the part Of
friends was necessary 10 induce him TO
consent to this publication, not because of
a modest reluctance TO rush into pri, {,
but for the reason that he considered it
undgnified for nobleman of Denmark
TO be the author OF booki
A Vanished Luminary.
An important question in cosmlc as
tronomy is opened by Tycho's star. Did it
really disappear from the heavens when
he saw it no more, or had its lustre simply
been reduced below the visual power of
the unaided eye? Unfortunately. Tychos
observations of the stars position in the
constellation were necessarily crude. He
possessed no instruments of precision such
as we now have al our disposal, and SO his
work gives US only a rather rough approx
imation of the true place CT the star. a
small circle might be imagined on the sky
Of size comparable with the possible err
roTs of Tychos observations. We could
then say with certainty that his star must
have been situated somewhere within that
little circle but it is impossible to know
exactly where. Now it happens that our
modern telescopes reveal the existence Of
several faint stars within the space COW
cred by such circle. Any one of these
would have been too small for Tycho to
see and therefore any one Of them may
be his once brilliant luminary reduced TO
a state of permanent or temporary semi
darkness. These considerations are in
deed, OF great importance in explaining the
phenomena OF temporary stars. If Tycho
had been able to leave us a more exact
determination of his stars place In tbs
sky and even il our most powerful instru-
ments could not show anything in that
place today, we might nevertheless theor
ize on the suppositicn that the object still
exists. but has reached q condition almost
entirely dark. Indeed, the latest theory
classes temporary stars among those
known as variable For many stars are
known to undergo quite decided changes
in brilliEncy; possibly Inconsistency of light
Is the rule rather than the exception. But
while such changes. when they exist are
too small to be peTceptible in most cases,
there is certainly a large number of OBJ
serVabla vaTiables, subject 10 easily mea-
surable alterations of light.
Astronomers prefer TO see in the phenom-
ena OF temporary stars simple cases OF va
Ration In which the increase OF light is
sudden, and followed by a gradual diminu-
ton Possibly there is then long period
of comparative or even complete darkness,
to be followed as before by sudden blaz-
ing up and extinction. No temporary star
however, has been obseroyd to reapeDar
in the same celestial place where once had
glowed its sudden outburst. But cases are
not wanting where incandescence has been
both preceded and followed by a continued
existence, visible. though not brilliant.
For such cases as these 1t is necessary
to come down to modern records. We can
not be sure that some faint star has been
temporarily brilliant unless we actually see
the confagration itself, or are able to
make the identity Of the object before and
after the event perfectly certain by the
aid of modern instruments of precision
But no one has even seen the smoldering
fires break out Temporary stars have al
ways been first noticed only after having
been active for some days. So we must
perforce fall back on instrumental iden-
tifcation by determinations of the stars
exact position upon the celestial vault.
Some time between the 10th and 18th
of May. in the year 1868, the ninth star in
the list OF the known "temporaries" ap-
peared. 1t was fully equal to the second