The San Francisco call., 1906-06-24
BY 4. Russell Bond.

About three hundred years ago d
German astronomer who was gazing up
al the southern skies was astonished
70 observe bright star which he had
never before seen in that part of tke
heavens. For a few days the star lin
gered and then vanished from view.
Strange TO say. this phenomenon was
repeated about eleven months later,
and thereafter IL happened almost reg
ularly every eleven months. Some
times the star blazed up to a remark
able brilliancy. but this never lasted
more than d few days at a time. So
extraordinary was its behavior that
the star was called Mira, the wonder
full" This was before the days of the
telescope.
Now we can see the star almost any
night during the winter month with
even a field glass. because il is seldom
fainter than the seventh magnitude,
but 1t still blazes up remarkably at
more or less regular periods of about
eieven months
This was the first discovery of a
''variab bic" star It was thought 10 be
an exceptional case at first, but since
then many hundreds of variable stars
have been discovered, some having a
wide range of iuctuation and others
showing only a slight irregularity in
the light they cast
Professor Pickering, director Of the
Harvard Observatory, recently issued a
circular calling attention 10 twenty
two new variable stars discovered by
Miss Henrietta Leavitt in the last two
years in a limited area of the heavens
Professor Pickering advocates a plan
Of systematically photographing the
entire heavens in sections of small area
80 that all the stars down to the faint
est ones visible in the largest tele-
scopes may be numbered and their po-
-a4
a view TO discovering all the variable
stars.
This seems a stupendous piece of
work. as il would involve the study of
at least 50e0O00e stars. But If the
work is co-operativsly carried out, each
observatory being assigned its own
particular field. il is thought proba BILE
that the task can be accomplished in a
single genera ticn.
Study Of the "a riable stars is one of
the newest branches of astronomy. and
IS particularly interesting to amateurs
because valuable discoveries can be
made in this branch Of work without
any expensive Instruments, and even
without the use Of a telescope. a lay
man may 1hus follow a line of research
which viii rot only prove very fas-
cinating and instructive. but which will
materially assist astronomers in their
work.
The brGhtest star mot planet) IN the
sky when viewed with the naked eye
appears as only a point OF light with
beams or lines radiatiog in all direc-
tioaS. View this same star through a
field gless. magnifs-ing four times, and
stil II appears as only point OF light
with the r3clatiEg beams less prom
inent. Use large telescope ma gnify-
ting eco times. but the star will appear
even smaller because of the absence Of
the false radiation. and even when ex-
araiued through the great Yerkes tel
escope, which rcasnifes 5000 times, the
star is sin merely g tiny point of light
with no .nea suTs tie diameter. The fact
CT thc matter is that tho stars are SO
far from US that. even if they should
grow 10 5000 times flleie present diam
eter. they would suil appear 10 Us no
larger than ? dot.