The San Francisco call. [volume], January 27, 1907, Page 6, Image 6

About The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913

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HIDDEN SECRETS
OF THE SUN TO BE PROBED
FROM A CALIFORNIA
PEAK
Enos Brown
I*C cstronomira.l. as In all other *el
cnees, tiie tendency of expert* Is
toward specialized "work. In medi
cine this is true, as all know, but
in astronomy, with the \u2666normoas cost
of apparatus and the scanty Income
Bljowed most observatories, it has not
hr"t\ possible for nr.y one Institution
to r!v« sprr!rl PttT.tion to one par
ticular subject or to devote time or
attention to one »o'« tobject of re
search. Until the Curncsie Institute
r.r Washington was founded the means
adequate to maintain an observatory
devoted solely to solar research alone
was not available.
Astronomers had, dreamed of such a
foundation, but hardly expected to see
the dreams realized In their day. No
ec-oner did the munificent offer mate
rialize than « committee of most emi
nent specialists put forward the pro
ject of n. folnr observatory. The effort
va« not a va^n ©tie and ilie result in
cecu in the magnificent observatory
on Mount 'Wilson. Oal.. an flevation of
a range of" mountains traversing the
county *>f I>os Angeleg.
Uvery astronomer, professional or
otherwise, is familiar with the detail
of the great instrument erected by
Lord Rosse at ParEonfttown. Ireland. In
dimensions every telescope employed
proved to Jxird Itosso's bore as little
iv comparison t'J that "noMe-man's as
Bunker Uil\ monument in height docs
to the Eiffel Tower. To the time worn
Lord Ttosse contemplated the erection
of an instrument co transcendently
great in its dimensions astronomers
had been content with means infinite
ly less powerful than thft ones with
xvhk-lj, every observatory in the worlJ
of any pretension* is equipped. Galileo
made his sublime discoveries with a
telescope having an aperture of but
four inches. The largest instrument
through which Newton gazed had an
object glass not greater than sbc
Inches, yet with the simplest means
those inspired observers were enabled
to lay broad and deep the foundation
upon which the eternal principles or
modern .astronomy are founded' and
dust Ktand for all time to come.
The Hersrhels -were, perhaps, the
most prolific of the groat astronomical
discoverers. What might not those
*ncn have seen had they been acquaint
ed with the powerful instruments of
the present day? With their imperfect
Instruments, visually faulty, they pene
trated deeper into space and extended
«he world's know ledge of terrestrial
mechanism to a. degree surpassing:
their predecessors in the scicuco and
were equipped with irlescopeas no more
powerful than are common to, the
smallest observatories of the present
day. The Herseheln were fathers of
the great instruments now employed.
Their wide diversity of scientific gifts
enabled them' to realize the inadequacy
cf the mechanical tools*, astronomer* •
of their time were compelled to employ,
and they brought their great powers
to the task of discovering certain great
principles in the fabrication of tele
eeor»e«, and, in fact, constructed with
their own hards instruments which far
eurpassed In power, size and perfection
of mechanical detail all those iv use
brfor* 1 their day.
Lord Rossc's Big Reflector
7>ord rio**»>'e telescope v»s a reflector
*rith a mirror seventy-two inches in <Si
euneter. With unlimited means tho
jioblernan was able to epir^oy ib«
xnott experienced mechanics in con-
Rtructing th« Ktreat Instrument tvhioh
lisx immortalised him. Astronomers
believed a new epoch about to
dawn upon the sublime science when
tho. great Rosse telescope was turned
toward space, and that terrestrial se
crets which bad always b*en the de
epair of .observers would yield to its
power and revelations.
Ih 1779 Sir William Herschd con
structed a reflector seven feet in diam
eter, and with it mado a series of re
markable discoveries. He it was who
I\rnt realized how boundless th«
hezvens were and. ventured to number
the stars. His studies of the ncbu>a
were far in advance of his predecessors
and laid the foundation upon which the
great Frenchman, La Place, laid li's
•"nebular theory," -which explained the
origin of worlds.
All the ' high hopes entertained of
Lord Rosse'fl groat telescope were dis
appointed. Atmospheric and climatic
conditions in ihv moist climate of Ire
land proved urffavor.-ible. The mechan
ism of the giant teJescope proved de
fective. Optical science was not suffi
ciently advanced md the nobleman,
after a vast outlay. iyas compelled to
realize that his telescope was a fail
ure. In so far as power to extend
the ranpe of tele*cope vision was con
cerned. J.iord Ilosse's instrument proved
impotent. The only service the great
telescope has rendered astronomers is
to demonstrate defects which subse
quent builders might avoid. Lord
House's srreat reflector never advanced
tlie science of astronomy a single
step. Its great 71-inch fflass Is in
capabU* of an observation which a. com
petent astronomer would regard as con
clusive. And, as Car as accuracy,
power and scrviee-ablcness arc con
cerned, it Is surpassed in every par
ticular by the twenty-four inch reflec
tor of the Snow telescope at Mount
Wilson.
It was due to a communication ad
dressed to the Carnegie Institute at
Washington by Dr. 8. P. Langley of
the Smithsonian Institution that the es
tablishment of an observatory at a very
high* altitude for the special purpose of
studying solar radiation was finally
brought about. This communication was
re.ferrcd to a committee of astronomers
of especial distinction, who indorsed a
report of Professor W. J. Hussey ad
x-orating Mount Wilson, near the city
of Pasadena, in Southern California, aa
possessing the requisites of atmospheric
conditions of superior character, as a
*ite for the proposed observatory. Pro
fessor <Jeorße I- Hale, director, snb-
KfqQenUy conducted independent Xests
and ohf erv.atlons l>efnro this site was
finally selected. Mount Wilson is o»o
of many summit* that form the south
ern boundary of Uie tfirrra Madre. range,
and ja about thirty miles from the Pa
cific Ocean. In addition to the ad
vantages of a pure ami stable atmos
phere the mountain is distinguished
by its springs of water which gush out
In ropious volume near the summit.
Wind movement at the summit is ex
ceptionally low. The air is wonderful
ly transparent. Tests of the definition
of celestial objects were unusually
sharp; moreover, an observatory thus
located, while sufficiently retired, ia ac
cessible to great cities and in easy com
munication witli all the world.
Before Mount Wilson was finally de
cided upon as the site for the great
solar observatory Professor Hale.- in
March, 1901, conveyed a coelostat of
fifteen-inch" aperture to the summit,
and the results from a series of ex
perimental observations were so emi
nently satisfactory that the professor
concluded "Sfrount Wilson met in a very
remarkable degree the requirements
of a site." Later a grant of $150,000
for building the observatory, and Its
maintenance for 1905 was made, and
the observatory was definitely estab
lished. . .
Mount Wilson having been selected
as the site of the observatory, the.
preparations necessary -to construct a
trail to the summit, sixteen miles,
homes for the resident observers, shops
for the manufacture and repair of in
struments. V7ith foundations and shel
ter for the telescopes, spectroscopes,
spectroheliographs and the numberless
paraphernalia of an observatory- of. the
first order, were proceeded -with and rap
idly completed. At this writing Mount
Wilson- Solar Observatory has taken its
place among the world's institutions' as
a contributor to knowledge whereby
more exact, definite and authoritative
information of solar constitution, mo
tio.n, atmosphere and all other phenom
ena connected with that great luminary
will result, not only in the. in T
t crease and diffusion of knowledge, but
in practical and? economic advantage to
all mankind.
Two Aspects of the Sun
The programme of solar research In
cludes two principal objects— first, the
study of the sun aa a typical star, with
special reference to stellar evolution;
second, th« study of th« sun as the cen
tral body of- the «olar system, with spe
cial refereneo to the relationship be
tween solar and terrestrial phenomena.
The investigations proposed Include, di
rect photography, photographic studies
of the solar atmosphere, epectroscopic
studies of the total solar radiation and
laboratory investigations. Each of the
proposed subjects embraces
tions which , only the most advanced
students in astronomy can understand,
but the results promise an .enormous
advance in the present knowledge of
everything appertaining to-, the »un and
it* functions.. ..
A programme so elaborately and ju»
diciously constructed demands .an
equipment of appliances and instru
ments specially devised and constructed,
and far superior to that owned by any
observatory in the world. Fortunately
for science, there were those among its
directors who estimated at -.full value
the immense service to bo rendered by
the proposed institution. The grants,
therefore, were sufficiently generous to
relieve the projectors from any anxiety
relative to financial resources. ; Pro
fessor Hale. with. his accomplished as
sociates and coadjutors, each selected
for eminence in some special feature of
solar Investigation, has been at no time 1
embarra«sed by scanty means or com-
pelled to appeal to patrons of science
for the funds without which the pro
posed comprehensive plans could not
have been undertaken.
There will be on the summit of Mount
Wilson a community , devoted to pure
science, something resembling the mon
asteries of. old. where, in the dark
ness .of the middle ages, there lived
men who passed out of tho world and
spent their life in the acquisition of
learning. To such institutions the
world owes tho preservation of knowl
edge ot classical ages and is ever ready
to acknowledge the enormous obliga
tion the monks of old rendered to all
future, generations. The buildings
erected for the observatory, which in
clude houses for the observers, as well
as elaborate constructions for housing
of necessary.instrumeiits. include a tem
porary building for the 15-inch. ceolostat
telescope: a casino for members of staff
and entertaining visitors; Snow -tele
scope building, shops and power-house;
storage battery house; pumping plant:
fire protection; the "Monastery," which
contains offices and living quarters;
general laboratory; warehouse; tele
phone line; library. -\u25a0/
The new shops for' the construction
of reflectors arid other appliances are
situated in the city of Pasadena. Tho
above structural . equipment has been
provided at considerable expense and
will fairly well -accommodate' present
requirements, but others must be
planned, more permanent' in 'character,
before the great observatory and its
equipment can be regarded as "fixed"
for all time; but, far more important
than all the rest, an observatory that
is to contain the great 5-foot reflec
tor now. nearly, readjf for mount.ing
and being fabricated at Pasadena under
the eye of, the faculty, and which will
combine every Equality- which,! the pres
ent advanced stage of optical knowl
edge can suggest, so ; that every per
fection niay, bo incorporated in the
gigantic glass which at no distant day
is to adorn the great solar observatory
in Southern California. The capabilities
of an- instrument provided with a per
fect mirrors <o~ inches to 'diameter can
be imagined. ; As before, stated, tho
Snow telescope, wjth 'mirrjor but . 24
Inches in- diameter, far ' surpasses ' in
power, definition and sharpness of de
tail the great imperfect 72-inch reflec
tor of Lordßoese.' With -the new 60
inch mirror, fabricated -with equal per
fection of the"; 24-lnch mirrttr of the
Snow telecope, -results infinitely finer
can! be accomplished. , The 'difference
between the two in power is far from
being expressed by the disproportion in
the diameter of the 'two mirrors. ,
• It, is upon the great mir
ror that .the place s in; science : to ' be oc
cupied by the i solar -.'; observatory >qf
Mount . Wilson Is 'to be Judged. n jThe
Crossley ; reflector; at t tho : Lick
vatory-; Is .^3C r : inches Hin diameter
and for photographic purposes Is prob
ably the. nearest perfect of Its kind In
the -world, yet even the.Crossley can
not be said to 'have fulfilled the ideals
Of astronomers. Even so powerful an
instrument has its limitations, and
though thousands, of dollars have been
spent on Its mountings and every sug
gestion that technical experience and
authority could adopt in fabricating a.
reflector that would be perfect has been
adopted, yet the Crossley fails In those
features in which results are just short
of the point where criticism fails' to dis
cern imperfections whose presence
throws doubt upon the most carefully
drawn conclusions. . '
An Ideal Reflector
Avoiding errors and taking advan
tage of all former experiences. \ the
great 60-inch reflector \ot- Mount
Wilson ought to- approach the'stand
ard of the most ideally perfect instru
ment ever at the service of an astro
nomical"" observer. In the construction,
of a 60-inch telescope reflector there
is not a step taken which does not em
ploy some principle of applied science.
The perfection of tho glass itself,. as '.t
issues from the mold, has to be assured
by the closest tests and most rigid
scrutiny. A minute bubble will render
the plate useless, therefore the " most
exact preliminary examination of the
great casting is": necessary. After
ward, the shaping' to a parabolic curve,
polishing " the surfaces. § silvering" ; ah«.T»
last of all. mounting the glass. i» at
tended with infinite care and the em
ployment, of most exact methods of
manipulation. The. great disk for the
60-inch reflector of Mount Wilson
.observatory- Is 8 : inches In -thick-,
ness andi weighs a ton. It was . past
at the celebrated glass works . of St.
Gobain. In the ctty of Paris, and is
beautifully tree from bubbles or oth«r
imperfections. » * • ,; ' ;
:\u25a0 Tho great mirror, as it now appears
in the workshop at Pasadena, is a circle
of fhe purest plato glass.- Its concave
form is perfect and ready for the silver
coating. • In . shaping the most exact
methods | are employed. -The slightest
imperfection is;not to be tolerated, for
the ray : from the faintest star would
Instantly detect a fault in the confor
mation^ ofy the glassJ The-. emery used
for the polishing 'is. of the and
the rouge without- a spfck, ~ else a
scratch which will deflect the ray. and
produce a blemish. : '
It;has taken. two years. to shape and
polish. A special automobile had to
be constructed to convey if to the.sum
mit -with \ absolute safety, 'and -when
there /a tube to : hold and a frame to
sustain the immense weight so absolute
ly solid "and well-balanced that the least
vibration is impossible. \u25a0So \u25a0 perfect ' is
the equipoise of < the great lnstrumcn t
when mounted that the. finger of a little
child can adjust Itto any ; direction. It
ls only when the plane of the great
mirror Is turned to receive the light
from a distant, star that its perfection
is assured- Jlad some one, after tho
preat glass had been polished, or
shaped, ready for silvering, merely rub
bod his palm across the face of it a
blemish would have been inflicted that
might haye been revealed only when
a ray from a star, a thousand mlllion
jnUlion miles distant, had first flashed
upon It. Even when the great reflec
tor is mounted and Its silvered disk
'« turned toward the burning sun, !m
lerfections will be manifested, not of
onstruction but of conditions. Abso
lute rigidity Is. Impossible. The heat
from the sun's rays will expand the
mirror.- Itself as well as the frame
which supports it to an extent which
mars the perfection of Its work. When
the Snow, telescope is in use a current
of cold air is driven through tha tube
in order that the effect of the heat may
be reduced to the lowest possible llm-
it. The morning and evening hours can
only ba employed when faultless ob
servations are demanded. In the lati
tude of Mount Wilson and at the alti
tude at which the great reflector is
mounted the heat Is too great at noon
to allow the mirror to be used at aIL
Such difficulties are universal and : to
be met with at any point on the earth's
surface. The special advantage of
Mount Wilson .os a solar observatory
is that ; with, the long . continuance of
clear weather other disadvantages
are; reduced, to an absolute min
imum..; No /site' in all" the world
oilers -more : perfect.' conditions.
The San Francisco Sunday Call.
' A-pcrti.nent inquiry would be. what is
hoped to gain by the expenditure of
vast amounts simply to observe th»
Bun, an object which, to tha ordinary
observer, is ever prominent?
What Is to Be Gained
To tho scientist such a quest'on
would aara superfluous. ;for the aun
holds in its flaming bosom every *«r.ret
of the universe. * Its influence on th*»
earth is tremendous. It ia probablo
that not a physJcal movement of any
nature Is manifested upon the earth,
that has not received its suggestion
from thio aun. Suppose the law off
storms could b« , discovered and the
initiative was found to be in tho sun.
Astronomers actually know but I!ttl«
about the great source of heat. pow<>r.
life and light. They can observe, but
cannot concelvs tn% cause of those Im
tnenss atmospheric cataclysms which
are ever at work on the surface and
visible through telescopes of averag*
power asd definition. Great eruptions
are at times taking place in
flaming gases are ejected to a i -rfr, t
of hundreds of thousands of miles: It
Is probable that every pulsation of tho
tua Is answered by a throb of tin
Mirth. Tho field of discovery opened to
tha observer of tha sun Is infinite ami
¥aat. promising results indescribably
ppr***. The photographs accompanying
this article are the very last and best
•f th« work of astronomical photog
raphy. Nothing near their clear defi
nition and perfect delineation has be-
Eor« bean seen. The great spiral nebula,
tn' Ursa. Major Is a distant object, a
test for th* 'highest power of a tele
acope. It was taken at Mount Wilson
by ths 24-lnch Snow reflector and ap
pears like a snowflake, but really is a
universe coming into being, so vast in
Its dimensions that mind cannot con
aeive It. If such startling work is pos
afble with a 24-Inch reflector, it is not
too much to believe that a glass two
and a half times the diameter will ac
complish results correspondingly great.
Mount Wilson is not only an observa
tory fitted with the largest and most
perfect reflecting telescope in tha
world, spectroscopes, heliographs, pho
tograph cameras especially constructed
tor terrestrial work, besides other in
rtruments calculated for the dolicat©
office of measurement and many others
besides, but it is also a center for the
wide dissemination of result?. Its
equipment Includes the finest special
ists in astronomical science the world
knows. Already the publications of
the faculty rank with the best in the
world. All of them are abstruse and
too technically written to be under
" stood by the common mind, but each
marks a step forward in knowl«^re
that concerns the sun. Here is a^.'st
of the treatises which the Mount Wil-
•on Solar, Observatory has thus far
published:
"Photographic Observations on tha
Spectra of . Sun Spo/s." by George E.
Hale and Walter S-. Adams: "A .Study
Of Solar Conditions for Solar Research
at Mount Wilson." "Latitude and Cojisri
tude of the Solar Observatory ."% *p^-^n
Spot Lines in the Spectrum of Arotur
us." Tne Spectroscope Laboratory of
the Solar Observatory," "Preliminary
Paper on the Cause of the Character
istic Phenomena of the Sun Spot Spec
tra,", "San Spot Lines on the Spectra of
Red Stars." besides others relating to
to« equipment of the observatory.