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.
[Illustration: Maps showing the principal stars visible from Lat. 40°
N. at 9 o'clock, July first.]
DRACO (drā´-ko)--THE DRAGON. (Face North.)
LOCATION.--About 10° from α Ursæ Majoris--from α to δ is 10°--slightly
south of, that is above, the line from α to Polaris, is Giansar, λ in
the tip of the Dragon's tail. Above λ, 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 β, 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.
[Illustration: DRACO]
LYRA (lī´-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.
ε is a pretty double for an opera-glass, and a 3" glass reveals the
duplicity of each star of this pair. ε is therefore a double double.
ζ is a double for a good glass.
β 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 γ Lyræ.
The noted ring nebula lies between β and γ. 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.
Public-domain text, read in full here on John Shaqi.
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