The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-09-24
THOSE THREE NORTH STARS
SOME OF THE WONDERFUL RESULTS
or SPECTROSCOPIC OBSERYATLOM
A Lucid Explanation of tho Use of the Spec
troscope in Revealing tho Presence OF
Invisible Heavenly Bodies and Deter.
mining Their Movements in the Sky.

A Lucid Explain alton of the Use of the Spec
troscope in Revealing tho Presence OF
Invisible Heavenly Bodies and Deter.
mining Their Movements in the Sky.
From tie Boston Evening TranscriDt
For many years scientists have known Of the
existence Of faint companion to the North
Star. 30 close and faint Is this ompanion that
owners OF small telescopes have often used II
TO test the power OF their eyes and instruments.
news has lately come from the Lick Observas
tory Mt Mt Hamilton. California. Of tho dlscov~
cry that Polarls consists OF three stars. two Of
which revolve around a common centre OF
gravity In about four days. At the same time
these two revolve around third star in much
the same way as the earth and moon rovolvs
around the sun. In this case the test 10 90
severe that no telescope can see the individual
stars. We can only infer their existence BY
noticing peculiar phenomena In the spec
trum Of Polaris
The stars. and in fact. all luminous bodiedSr,
emit series OF waves which are transmittec
oy the ether to us. Those waves that fall upon
the rstina OF our eyes produce a sensation that
we call light. In the case Of many millions OF
stars the effect OF these waves upon our eyes 10
inappreciable. Without the aid Of some instru.
ment such stars are invisible. The lens Of .
telescope condensss a large area OF waves into
small! compass, and this Increases the efYeot
uGon the eyes OF the observers. Consequently
much light as to make exceedingly faint stars
visible to the observer.
intsn.ity-that 10. color. When t certain DI mum:
Der OF wayes enter the eye each second We call
.ns we sa scs
| violet. &c. II the light gathered by some large
eocrs or s essr
ranged In tho order Of their wave length Such
| an arrangement OF colors has been named the
The spectrum Of the sun and Of m oct OF the
stars !, crossed byanumber Of flns, dark lines.
These ines are really gaps caused by the alb.
The lleht, before L can reach our TELESCOPES.
D.is Parts ' saS:
IN the spectrum caused by atmoe phe rio absorp-
Of liant aSt are .mittsd in ali directions alike But
rs WSs ss rssr are sS
rsspondinely lsnEthsned or cop,5ss, at ,, tSs
nss
in sound i en- tsn
Than when It Is Approaching, Thersiore. when
the star 10 approaehing the earth with q
ine' the color With the shortest wave isngth.
ths pss mt
Es,. ' sa s nn losn
| The first successful Investigation ON the
II the e Sc q oss wfs 1877 a s: f ss:s
f.: SG ,S,
a mile per second can BE- detected; ..
II two stars are so close together that they
w 5. 81
two stars move away from US. or toward us at
S% po % SHs9 But Il sss 5 81
a way that ons is approachin a while the other
L. Iseeding from the earth, then the +, lines
dsp ns T1 IN OPPOSITE SaIsections sometme:
only one OF the com nsnte Of binary star 10
tho t. b. f.
and sometimes reeedinG from the earth. The
end q tho spectrum. Hence when. a star 10
is close 70 4 fainter eompapion. The period
Of GRAVITY Is. 81 course oStsinsd directly from
J.s s.s :. tss 5 Il
Srsg Msiors he middle star In the hs1dS 81
showed that the lines srs somstI%es aoubis
ssTs aous as' star h' xsosa COM
"''s 81: s . iSs:' tss ss''s:. desssst:
| that when one 10 approaching the other 10 re-
| ceding from the earth. Twice during every
revolution they are nearly In q line with the
position and appear single.
Beta Persci. named Algol. furnishes an eF-
| am hle Of q binary star where only one OF the
| oompon ents 10 visible. vogel. at Potsdann In
| 1893. found from the displacement OF the lines
In the spectrum that AlRol 10 moving In small
orbit at the rate OF twenty-six miles per SEQ
ond; To ACCOUNT for this i is necessary to
AlRol and It's companion are moving around a
common centre Of gravity. In this instance
| the existence OF the dark companion 10 still
| further demonstrated by the variation in
Algol's light. Goodrieke in 1882 discovered
that Algol was . variable star. 1t Is usually
II SssetH nr sS. e. tS
in a few hours more rsgain It's normal
brightness, These minima in light OCCUR With
than seventy hours. guoh q phenomenon
naturally suRgests a partial eclipse caused By
some dark body periodically passing between
By a ~ q II. snogmeu, light gathering
aperture) Prot. Keeler has been able to
OF the Great Orion Nebula He finds that
It is .recedng from the earth at the
| ond While at the Allegheny Observs.
tory Prot Keeler used this same .spectrosoopto
neither solid nor liquid. They consist Of email
bodies that revolve around Saturn.
| Spectroscopio determ inatS,ns Of motion IN
| the line Of sight Is one OF the most promising
| nelde OF invest igation In astronomy. Many
problems have been solved that for centuries