A Field Book of the Stars Part 6

The equator, ecliptic, and equinoctial colure intersect each other at a point close to the star ?. This is called the autumnal equinox.

The star e is known as the "Grape Gatherer." It is observed to rise just before the sun at vintage time.

Within the rude square formed by Denebola, and e, ?, and , Virginis, the telescope reveals many wonderful nebul; hence this region of the sky has been called "The Field of the Nebula."

Spica is an extremely beautiful pure white star. It rises a very little south of the exact eastern point on the horizon.

? is a fine double star for a small telescope.

Virgo is mentioned by the astronomers of all ages. By the Egyptians it was intended to represent the G.o.ddess Isis, and the Greeks knew it as Ceres. Spica represents the ear of corn held in the Virgin's left hand.

[Ill.u.s.tration: VIRGO]

CANES VENATICI (ka-nez ve-nat-i-ci)--THE HUNTING DOGS. (Face Northwest.)

LOCATION.--Cor Caroli, the bright star in this constellation, when on the meridian is about 17 south of e Urs Majoris. A line drawn from ?

Urs Majoris, through Berenice's Hair, to Denebola, in Leo, pa.s.ses through it.

The dogs, Asterion and Chara, are represented as being held in leash by Botes, the herdsman, in his pursuit of the Great Bear.

Cor Caroli is in the southern hound, Chara, and represents the heart of Charles II of England. It is a beautiful double star in a small telescope.

The so-called "Diamond of Virgo," is clearly shown on this plate. It is formed by connecting with lines the stars Cor Caroli, Denebola, Spica, and Arcturus.

The fifth-magnitude star La Superba, about 7 north and 2 west of Cor Caroli, is especially noteworthy because of the flas.h.i.+ng brilliancy of its prismatic rays.

[Ill.u.s.tration: CANES VENATICI]

METEORIC SHOWERS.

JULY TO OCTOBER.

+---------------+--------+----------------+---------------+----------------+--------+ | | | | | Other Dates | | |Name of Shower | Date | Radiant Point |Characteristics| of |Location| | | | | | of Observation | | +---------------+--------+----------------+---------------+----------------+--------+ | | | Between | | June 13-July 7 | | |Vulpeculids or | July 4 | Cygnus and | Sw. | Apr. 20, | E. | | Eta Sagittids | | Delphinus | | May 30 | | +---------------+--------+----------------+---------------+----------------+--------+ | | | Near Deneb | | July 11-19, | | | Cygnids |July 19 | (a) Cygni | Sh. Sw. F. | Aug. 22, July | E. | | | | | | 6-Aug. 16 | | +---------------+--------+----------------+---------------+----------------+--------+ | | | Between (a) | Sw. B. Sk. | July 23-Aug. 4 | | |(a)-() |July 25 | and | after | Sept. 15, | N.E. | |Perseids | | () Persei | 10 P.M. | Nov. 13 | | +---------------+--------+----------------+---------------+----------------+--------+ |Aquarids, a | | Near the | | | | |conspicuous |July 28 | water jar of | Sl. B. | | E. | |shower | | Aquarius | | | | +---------------+--------+----------------+---------------+----------------+--------+ |Perseids, fine |Aug. 10 | Near (a) | v. Sw. Sk. | | N.E. | |shower | | Persei | | | | +---------------+--------+----------------+---------------+----------------+--------+ |Kappa Cygnids |Aug. 17 | Near the | Sw. B.T. Sh. |Jan. 17, Aug. 4,| S.E. | | | | Dragon's head | |Aug. 21-25 | | +---------------+--------+----------------+---------------+----------------+--------+ | | | Near Capella | After 9.30 | Sept. 22, | | |Alpha Aurigids |Aug. 21 | (a) Aurig | P.M. | Oct. 2 | N.E. | | | | | v. Sw. Sk. | | | +---------------+--------+----------------+---------------+----------------+--------+ | Omicron | | Near the | | | | |Draconids. Rich|Aug. 22 | Dragon's head | Sl. T. | Aug. 21-25 | N | |shower in 1879 | | | | | | +---------------+--------+----------------+---------------+----------------+--------+ | | |Between Capella | After 10 | Aug. 21, 25, | | | Epsilon |Sept. 7 | and the | P.M. | Sept. 6-8, 21, | N.E. | | Perseids | | Pleiades | v. Sw. Sk. | Nov. 29. | | +---------------+--------+----------------+---------------+----------------+--------+ |Alpha Arietids |Sept. 21| Near Hamal | Sl. T. | Aug. 12, Oct. 7| E. | | | | (a) Arietis | | | | +---------------+--------+----------------+---------------+----------------+--------+ |Gamma Pegasids |Sept. 22| Near and S.E. | Sl. | July 31, Aug. | E. | | | | of Great Sq. | | 25, etc. | | +---------------+--------+----------------+---------------+----------------+--------+

The Perseids are of a yellowish color, and move with medium velocity.

Their line of flight is from northeast to southwest. They are probably visible for more than a month, from the latter half of July to the last week in August.

The August meteors are known as the "Tears of St. Lawrence."

The Abbreviations under _Characteristics_ are as follows:

v.--very Sl.--Slow Sk.--Streak-leaving meteors.

M.--Moderately B.--Bright T.--Train-leaving meteors.

Sw.--Swift F.--Faint Sh.--Short meteors.

THE CONSTELLATIONS OF AUTUMN.

[Ill.u.s.tration: Map showing the princ.i.p.al stars visible from Lat. 40 N. at 9 o'clock, October first.]

Ca.s.sIOPEIA (kas-i-o-pe-ya)--THE LADY IN THE CHAIR. (Face North.)

LOCATION.--A line drawn from d Urs Majoris, through Polaris, strikes a Ca.s.siopei. It is situated the same distance from Polaris as Ursa Major, and about midway between Polaris and the zenith in the Milky Way. Ca.s.siopeia is characterized by a zigzag row of stars which form a rude "W," but in mid-autumn, to an observer facing north, the "W"

appears more like an "M," and is almost overhead. Note the spot marked 1572. This is where a very famous temporary star appeared in that year. It was bright enough at one time to be seen in full suns.h.i.+ne.

The star ? is sixteen light years distant.

Caph is equidistant from the Pole, and exactly opposite the star Megres in Ursa Major; with a Andromed and ? Pegasi it marks the equinoctial colure. These stars are known as "The Three Guides."

The chair can be readily traced out; , a, and ? mark three of the four corners of the back, and d and e, one of the front legs. The word "Bagdei," made up of the letters for the princ.i.p.al stars, a.s.sists the memory.

The stars ? and are pointer stars to a fifth-magnitude star the lucida of the asterism Lacerta, the lizard about 15 from .

Ca.s.siopeia makes an excellent illuminated clock. When is above Polaris it is noon, when it is in the west at right angles to its first position it is 6 P.M. At midnight it is on the northern horizon, and at 6 P.M. it is due east.

This is sidereal time which agrees with mean time on March 22d, and gains on the latter at the rate of two hours a month.

[Ill.u.s.tration: Ca.s.sIOPEIA]

CEPHEUS (se-fus) (Face North.)

LOCATION.--A line drawn from a to Ca.s.siopei and prolonged about 18 strikes a Cephei. The nearest bright star west of Polaris is ? Cephei.

Cepheus is an inconspicuous constellation, lying partly in the Milky Way. A view of this constellation through an opera-gla.s.s will repay the observer. Cepheus is characterized by a rude square, one side of which is the base of an isosceles triangle. Look for the so-called garnet star , probably the reddest star visible to the naked eye in the United States. The star ? has a blue companion star.

a forms an equilateral triangle with Polaris and e Ca.s.siopei.

It is claimed that Cepheus was known to the Chaldans twenty-three centuries before our era.

Surrounding d, e, ?, and ?, which mark the king's head, is a vacant s.p.a.ce in the Milky Way, similar to the Coal Sack of Cygnus.

About 4 from ?, in the direction of ? is a pretty pair of sixth-magnitude stars.