COMA BERENICES
CANIS MINOR (ka´-nis mi´-nor)-THE LESSER DOG. (Face West.)
Table of Contents Location.-Procyon, the Little Dog Star, lies about 23° south of Pollux, in Gemini. A line drawn from Nath, in Auriga, to Alhena, in Gemini, and prolonged about 18°, reaches Procyon.
Procyon is equidistant from Betelgeuze in Orion, and Sirius in Canis Major, and forms with them an equilateral triangle. It forms a large right-angled triangle with Pollux and Betelgeuze.
The light from Procyon is golden yellow. Four degrees northwest of it is the third-magnitude star Gomeisa. The glass shows two small stars forming a right-angled triangle with it.
Procyon was distinctly mentioned by Ptolemy. It rises in this latitude a little north of east about half an hour before Sirius, the Dog Star, hence it was called Procyon from two Greek words which signify "before the dog."
Procyon is one of our nearest neighbors in space, at a distance of ten light years, and is attended by a very faint companion which is only visible in the largest telescopes.
CANIS MINOR CORVUS (kôr´-vus)-THE CROW. (Face South.)
Table of Contents Location.-A line drawn from the Bee Hive, in Cancer, through Regulus, in Leo, and prolonged about 40°, ends near the conspicuous quadrilateral which distinguishes Corvus. The brightest star in this region of the sky is Spica, in Virgo. It lies about 10° northeast of Algorab.
? is a double star for an opera-glass. A faint pair of stars lie close below and to the west of ß. The Crow is represented as standing on, and pecking at, the coils of Hydra. The star Al Chiba is in the Crow's bill.
Corvus was known as the Raven in Chaucer's time.
d is an interesting telescopic double.
A line drawn from ? to ß Corvi and prolonged twice its length locates the third-magnitude star ? Centauri in the right shoulder of the Centaur. The brightest stars in this constellation are not visible in this latitude.
CORVUS CRATER (kra´-ter)-THE CUP. (Face South.)
Table of Contents Location.-Crater is situated 15° west of Corvus, and due south of ? Leonis. It is easily distinguished by reason of a beautiful and very striking semicircle of six stars of the fourth magnitude, forming the bowl of the cup.
The constellation resembles a goblet with its base resting on the coils of Hydra.
The star Alkes is common to Hydra and Crater, and may be seen 24° southeast of Alphard in the heart of Hydra. It is distinguished by its forming an equilateral triangle with a and ?, stars of the same magnitude 6° south and east of it.
Corvus and Crater are to be seen half-way up the southern sky during the early evenings in spring.
d is now the lucida.
Crater is situated at about the centre of Hydra and is on the meridian, April 26th. Owing to its many faint stars it is best seen on a clear moonless night.
The zodiacal light is well worth observing at this season of the year. It is to be seen in the western sky shortly after sundown, and is most intense during the evenings of March.
CRATER METEORIC SHOWERS.
Table of Contents APRIL TO JULY.
Name of Shower Date Radiant Point Characteristics Other Dates
of
Observation Location Beta or Mu
Draconids
Beta Serpentids Apr. 9-16
Apr. 18 The Dragon's head
The Serpent's head Sw. F. Apr. 17-25 N.E.
S.E. Lyrids,
rich shower Apr. 20 About 10° from
Vega toward
Hercules V. Sw. N.E. Eta Aquarids,
fine annual shower May 6 Near the Water
Jar Sw. Sk. After 2
a.m. E. Alpha Coronids,
well defined in 1885 May 11 Near Gemma
(a) Coronæ B. Sl. F. May 7-18 N. Iota Pegasids,
well defined shower May 30 Between Cygnus
and the Great
Square Sw. Sk. May 29-
June 4 after
10
p.m. N.E. Beta Herculids
Beta Ophiuchids June 7
June 10 Near the Crown
About 8°S. of Ras
Alhague Sl. B.
Sl. A fire ball
radiant
June 10, 13 S.E.
S.E. Delta Cepheids June 20 About 13° from
(ß) Cassiopeiæ Sw. June 10-28,
July 19, Aug.
25, etc. N.
The Abbreviations under Characteristics are as follows:
V.-very. M.-moderately. Sw.-swift. Sl.-slow. Sh.-short. B.-bright. F.-faint. Sk.-streak-leaving meteors. T.-train-leaving meteors.
THE CONSTELLATIONS OF SUMMER.
Table of Contents Maps showing the principal stars visible from Lat. 40° N. at 9 o'clock, July first. DRACO (dra´-ko)-THE DRAGON. (Face North.)
Table of Contents Location.-About 10° from a Ursæ Majoris-from a to d is 10°-slightly south of, that is above, the line from a to Polaris, is Giansar, ? in the tip of the Dragon's tail. Above ?, and almost in line with it, are two more stars in Draco, which form with two stars in Ursa Major a quadrilateral. (See diagram.) Draco now curves sharply eastward, coiling about the Little Bear as shown, then turns abruptly southerly, ending in a characteristic and clearly defined group of four stars, forming an irregular square, representing the Dragon's head. This group is almost overhead in the early evening in summer. The star in the heel of Hercules lies just south of the Dragon's head. The brilliant Vega will be seen about overhead, 12° southwest of the Dragon's head. Eltanin, one of the Dragon's eyes, is noted for its connection with the discovery of the law of aberration of light. It is of an orange hue, while the star ß, near it, is white. Note Thuban, once the Pole Star, at one corner of a quadrilateral that Draco forms with Ursa Major.
Thuban could be seen by day or night from the bottom of the central passage of several of the Pyramids in Egypt.
The rising of Eltanin was visible about thirty-five hundred years b.c. through the central passages of the temples of Hathor at Denderah. The Egyptians called Draco "The Hippopotamus."
Vega and the four stars in the Dragon's head offer an opportunity to compare the first five stellar magnitudes with which all should be familiar.
DRACO LYRA (li´-ra)-THE LYRE.
Table of Contents Location.-Lyra may be easily distinguished because of the brilliant Vega, its brightest star, which is situated about 12° southwest of the Dragon's head. It is unmistakable, as it is the brightest star in this region of the heavens, and the third brightest in this latitude. In July and August Vega is close to the zenith in the early evening.
The six bright stars in Lyra form an equilateral triangle on one corner of a rhomboid. A very characteristic figure.
e is a pretty double for an opera-glass, and a 3" glass reveals the duplicity of each star of this pair. e is therefore a double double.
? is a double for a good glass.
ß is a variable, changing from magnitude 3.4 to 4.4 in twelve days. At its brightest it is about equal to its near neighbor ? Lyræ.
The noted ring nebula lies between ß and ?. A 3" glass reveals it but a powerful telescope is required to render its details visible.
If the distance from the earth to the sun equalled one inch, the distance from the earth to Vega would be 158 miles.
Vega was the first star to be photographed, in 1850. It is visible at some hour every clear night, and has been called the arc-light of the sky. Its light has the bluish-white hue that suggests "a diamond in the sky."
The spectroscope reveals that Vega is a star probably only in its infancy, as hydrogen is its predominating element.
LYRA CYGNUS (sig´-nus)-THE SWAN, OR THE NORTHERN CROSS.
Table of Contents Location.-Deneb, the brightest star in Cygnus, is at the top of the cross, and a little over 20° east of Vega. It forms a triangle with Vega and Altair in Aquila-Altair being at the apex, about 35° from Deneb and Vega.
ß Cygni is at the base of the cross, and a line drawn from Vega to Altair nearly touches it. It is a beautiful colored double for a small telescope.
Note "61," one of the nearest stars to us. It was the first star whose distance was measured (by Bessel in 1838). It is a double star and 10.4 light years distant.
The cross is nearly perfect and easily traced out. It lies almost wholly in the Milky Way.
Note "The Coal Sack," one of the dark gap in the Milky Way.
Cygnus contains an unusual number of deeply colored stars and variable stars.
? Cygni has a...
