The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1902-12-03
Scientific American.


The finest region in all the starry
heavens now occupies the eastern sky.
In one-tcnth OF the total area Of the visi-
bic heavens It includes eight out Of the
sixteen brightest stars visible in our lati-
tudc. As we turn our gaze eastward at
our customary hour OF O'Clock on De-
cember Is. we find near the horizon the
two dog-stars. Sirius and Procyon. The
latter is nearly due east. and Is some
what higher up than the former. which,
even at its present low altitude. gives
evidence Of its surprising brightness
Both these stars are among our near
neighbors in space, and both are attend
ed by faint companions, visible only with
the largest telescope.
Above Sirius is Orion. with the bright
red star Betelgeuse on the left. and the
still more brilliant Rigel lower down on
the right Gemini. which lies above
Procyon. has also a pair Of bright stars.
The upper one is named Castor. and the
lower Pollux. still higher up are AUriga
(above CeminD and Taurus Cabove Orion
bearing the bright stars Capella and Al
debaran
The long line Of faint stars which be-
gins at RigeI and can be traced west
ward. then southwark. and then back to-
ward the southeast. forms the coustella-
tion Eridanus It's one bright star.
Achernar. which nearly equals Rigel.
can be seen az this season low on the
southern horizon from places south OF
latitude 30 degrees. The large constel-
lation Of Cetus. the Whale. occupies a
great part Of the southern sky. The
monsters head is marked by an irregu-
lar pentagon Of small stars. which Is
now on the meridian. about half way up
to the zenith. The brightest star in the
constellation. Beta Ceti lies nearly 80
degrees to the westward, and is the only
conspicuous one in the southwestern
sky.
Aries IS nearly on the meridian above
Cetus. and Perseus is directly overhead
Observable m-nima of Algol viii occur
on the 18th at Il D. m. on the 18th at
D. m. and on the 18th at p. m. An
dromeda and Pegasus are the most con-
spicuous consultations to the vert OF
the zenith, Cygnus IS still visible in the
northwest. and Lyra is low on the hori-
zon. Ursa Minor and Draco are below
the pole, Ursa Major coming up to the
east Of il, and Cassiopeia and Cephus
high on the west.
We have had some occasion In the fore
going TO refer 70 the distances Of certain
stars. Nothing in all the realm CT as
tronomy impresses the imagination more
than these enormous distances. Indeed,
they are so vast that it is hardy credi-
bic that they can be measured at all.
Measuring the Heavens.
The principle used by astronomers to
determine them is exactly that Of the
range-hnder employed by modern gun
ners. Bearings are taken on the distant
target from two points as far apart as is
practicable. Knowing the distance be-
tween these points, the distance Of the
target can be calculated from the differ
ence Of its bearing at the two points.
When We come to apply this method 10
The stars. we find that the whole diane
ter OF the earth is far too short a base
line. Fortunately. we have a longer one
the diameter Of the earth's or
bit. BY taking observation OF q star at
properly chosen dates six months apart.
We have a base 1s6 900 900 miles long
and can proceed with some chance Of sue
cess.
The next question is: How can we
measure the bearing Of the start with
accuracy The best way is TO
choose some small stars near the one 20
be investigated. and use them as points
Of reference. Such small stars are usual
~ so far away that their change Of bear
ing may be neglected while the nearer
sta appears 20 be slightly displaced with
reference 90 them. Occasionally the faint
star chosen is no farther of than the
other. or even nearer. This is the case
with Rigel. which has ninth magnitude