Evening star. [volume] (Washington, D.C.) 1854-1972, 1900-11-03
NOVEMBER HEAVENS
Interesting Information for Amateur
Astronomers.
TECHNICAL TERMS ILLUSTRATED
Why the Leonids Failed to Show
Up Last Year.
IICAL TERMS ILLUSTRATED
TO LOCATE THE STARS
for The Evening Star.

The principal consultations favorably sit |
uated for inspection during the early part
of the month are Cassiopeia and the ORA
gon in the north, the Swan or Northern
Cross in the northwest, Pegasus in the /
southwest and the combination of Andro-
media, Aries, Perseus and Taurus, which
occupy the eastern quarter of the heavens.
All of these consultations are well above
the horizon at o'clock, Cassiopeia, An
dromeda and Pegasus being then nearly
overhead. In the east Orion is rising, Her
cules is setting in the northwest and di-
rectly beneath the Pole star. in its lowest
position, may be seen the Great Dipper in
the Ursa Major.
The first-magnitude stars now above the
horizon at the hour named are Capela in
the northeast; Aldebaran, at somewhat
less altitude in the east; Betelgeuse, below
Aldebaran and barely above the horizon;
Rigel at about the same altitude between
east and southeast; Fomalhaut, little west
of south; Affair, in the west, and Vega, in
the northwest.
The Square of Pegasus has just crossed
the meridian. The two stars which form
the eastern side of this striking quadrangle
lar figure lie very nearly in line with the
vernal equinox, thus serving as pointers
by means of which this very important as
Economical position can be located readily
1t is situated south OF the square, at dis
lance from the lower of the two pointers"
about equal to their distance apart.
Celestial Cartography.
The heavens are now we'll posed for an
elementary lesson In celestial cartography.
We will survey them for few moments
from this point of view, for the purpose OF
gaining clear idea of the meaning of sew
eral terms which one continually comes
across in his astronomical reading.
The Verna1 equinox of which the position
baa i,1St iS he a
which the sun in its annual (apparenD pas
sage round the heavens crosses the celes-
tial equator from south to north, about the
21st of March The sun then enters the
sign Aries, which has been regarded
from time immemoriaI as the first Of the
twelve zodiacal signs This point has
therefore. been chosen as a convenient point
from which to reckon distances in charting
the heavens.
Positions on the celestial sphere are 10
Gated by right ascension and ''declina-
ton" which correspond very closely with
terrestrial longitude and latitude. Right
cension, which answers to longitude, Is
reckoned from the vernal equinox, or, to
speak more strictly, from the Prime Me-
ridian," which passes through the equinox,
| just as longitude is reckoned from the me-
ridan of some national observatory-that of
| Greenwich, for example. 1t differs from
| longitude however, in being reckoned in
| one direction only viz, from west to east
| the direction of the suns apparent annual
ACKNOWLEDGEMENTS longitude is reckoned
| both east and west That is to say, right
ascension is reckoned up to 56O degrees.
| The reckoning is commonly made, however,
| not in degrees, but in hours of 10 degrees
each, the entire circuit of the heavens be-
ing divided into twenty-four hours What
| are called meridians of longitude on ter
| restrial may become hour circles on a
chart of the heavens.
Declination corresponds exactly with ter
| restrial latitude, being reckoned in precisely
| the same way, that is, IN degrees from the
| equator to the poles. Just as we have
north and south latitude, SO we have decli-
| nation north and south
| Terms Illustrated.
| few illustrations will make this matter
| clear Let US consider first the positions of
| the four fundamental points in the heavens.
| There are two equinoxes, Numerically op-
| posite to each other on the celestial sphere,
and midway between them, in the suns
| path are the two solstitial points, at which
| the sun attains its greatest northern and
| southern declination of 231a degrees. The
right ascension of the vernal equinox is
zero, this being the starting point in the
reckoning; that of the summer solstice,
or e-quarter of the way around, toward the
| east is six hours; that of the autumnal
equinox, one-half Of the way around, Is
twelve hours; that of the winter solsuce,
| three ourths of the way around, Is eighteen
| hours another quadrant of six hours brings
us again to the vernal equinox and COM
| Dletes the circuit.
AS further 1lluStraClOn, the right aSceI-
! sion of the star Aldebaran is about hours
20 minutes; it's declination, north, Is 16 de-
grees Is minutes. This means that Aide
baran is four and half hours east of the
| prime meridian, and 16 degrees and IS min
| utes north of the celestial equator. Its po-
| stion is thus defined with the same precis-
| ion as when the city of Washington, for eX-
| ample is said to be in longitude n degrees
| west from Greenwich, and in north latitude
| 3S degrees so minutes
| MefenrS
| The Leonid meteorS may be expected to
| put in their usual annual appearance about
| the middle Of the month, probably being
| the most numerous on the morning of the
| 18th. Their failure to appear In force last
year, as was confidently expected, renders
it unsafe to make any prediction regarding
| them this year. DR.. Stoney attributed the
| failure of the anticipated shower in 1899 to
! a perturbance of the meteor swarm during
| the sun by the planets Saturn and Jupiter,
| the path of the meteors having been there
! by shifted to such an extent that, instead
| of intersecting the earth's orbit as 1t for
| merly did, 1t now passes, according to his
| calculations, a million miles or so inside of
| that orbit. If this new arrangement con-
| tinues, 1t is not likely that any shower of
these meteors will again be witnessed.
though struggling Leonids may continue to
| These meteors aIl-shoot from the direction
| of point near the center Of the Sickle
| in Leo.
| On the 23d and from thar date to the
| end of the month the Andromeds may be