dra.

In the 5th century B.C. the Athenian astronomer Euctemon, according to
Geminus of Rhodes, compiled a weather calendar in which Aquarius,
Aquila, Canis major, Corona, Cygnus, Delphinus, Lyra, Orion, Pegasus,
Sagitta and the asterisms Hyades and Pleiades are mentioned, always,
however, in relation to weather changes. The earliest Greek work which
purported to treat the constellations _qua_ constellations, of which we
have certain knowledge, is the [Greek: Phainomena] of Eudoxus of Cnidus
(c. 403-350 B.C.). The original is lost, but a versification by Aratus
(c. 270 B.C.), a poet at the court of Antigonus Gonatas, king of
Macedonia, and an [Greek: Exegesis] or commentary by Hipparchus, are
extant. In the [Greek: Phainomena] of Aratus 44 constellations are
enumerated, viz. 19 northern:--Ursa major, Ursa minor, Booetes, Draco,
Cepheus, Cassiopeia, Andromeda, Perseus, Triangulum, Pegasus, Delphinus,
Auriga, Hercules, Lyra, Cygnus, Aquila, Sagitta, Corona and
Serpentarius; 13 central or zodiacal:--Aries, Taurus, Gemini, Cancer,
Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces
and the Pleiades; and 12 southern:--Orion, Canis, Lepus, Argo, Cetus,
Eridanus, Piscis australis, Ara, Centaurus, Hydra, Crater and Corvus. In
this enumeration Serpens is included in Serpentarius and Lupus in
Centaurus; these two constellations were separated by Hipparchus and,
later, by Ptolemy. On the other hand, Aratus kept the Pleiades distinct
from Taurus, but Hipparchus reduced these stars to an asterism. Aratus
was no astronomer, while Hipparchus was; and from the fact that the
latter adopted, with but trifling exceptions, the constellation system
portrayed by Aratus, it may be concluded that the system was already
familiar in Greek thought. And three hundred years after Hipparchus, the
Alexandrian astronomer Ptolemy adopted a very similar scheme in his
uranometria, which appears in the seventh and eighth books of his
_Almagest_, the catalogue being styled the [Greek: Ekthesis kanonike] or
"accepted version."

The _Almagest_ has a dual interest: first, being the work of one
primarily a commentator, it presents a crystallized epitome of all
earlier knowledge; and secondly, it has served as a basis of subsequent
star-catalogues.[1] The Ptolemaic catalogue embraces only those stars
which were visible at Rhodes in the time of Hipparchus (c. 150 B.C.),
the results being corrected for precession "by increasing the longitudes