Part 7

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.

METEORIC SHOWERS.

APRIL TO JULY.

+--------------------+---------+--------------------+---------------+-------------+--------+ | | | | | Other Dates | | | Name of Shower | Date | Radiant Point |Characteristics| of |Location| | | | | | Observation | | +--------------------+---------+--------------------+---------------+-------------+--------+ | Beta or Mu |Apr. 9-16| The Dragon's head | | | N.E. | | Draconids | Apr. 18 | | Sw. F. | Apr. 17-25 | | | Beta Serpentids | | The Serpent's head | | | S.E. | +--------------------+---------+--------------------+---------------+-------------+--------+ | Lyrids, | | About 10 from | | | | | rich shower | Apr. 20 | Vega toward | V. Sw. | | N.E. | | | | Hercules | | | | +--------------------+---------+--------------------+---------------+-------------+--------+ | Eta Aquarids, | May 6 | Near the Water | Sw. Sk. | After 2 A.M.| E. | | fine annual shower | | Jar | | | | +--------------------+---------+--------------------+---------------+-------------+--------+ | Alpha Coronids, | May 11 | Near Gemma | Sl. F. | May 7-18 | N. | |well defined in 1885| | () Coronae B. | | | | +--------------------+---------+--------------------+---------------+-------------+--------+ | Iota Pegasids, | | Between Cygnus | Sw. Sk. | May 29- | | |well defined shower | May 30 | and the Great | |June 4 after | N.E. | | | | Square | | 10 P.M. | | +--------------------+---------+--------------------+---------------+-------------+--------+ | Beta Herculids | June 7 | Near the Crown | Sl. B. | A fire ball | S.E. | | | |About 8S. of | | radiant | | | Beta Ophiuchids | June 10 | Ras Alhague | Sl. | June 10, 13 | S.E. | +--------------------+---------+--------------------+---------------+-------------+--------+ | Delta Cepheids | June 20 | About 13 from | | June 10-28, | | | | | () Cassiopeiae | Sw. |July 19, Aug.| N. | | | | | | 25, etc. | | +--------------------+---------+--------------------+---------------+-------------+--------+

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.

DRACO (dr[=a]'-ko)--THE DRAGON. (Face North.)

LOCATION.--About 10 from Ursae Majoris--from to is 10--slightly south of, that is above, the line from 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 , 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.

LYRA (l[=i]'-ra)--THE LYRE.

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.

is a pretty double for an opera-glass, and a 3" glass reveals the duplicity of each star of this pair. is therefore a double double.

is a double for a good glass.

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 Lyrae.

The noted ring nebula lies between 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.

CYGNUS (sig'-nus)--THE SWAN, OR THE NORTHERN CROSS.

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.

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.