Astronomicon, Book I

Gemini, Virgo Libra, Capricornus Aquarius, are nocturnal. The reason of this division he indicates in verses 211-213 by his arrangement of the names. The six diurnal signs constitute the trigon of Aries (Aries with Leo and Sagittarius) and the trigon of Cancer (Cancer with Scorpius and Pisces): Aries is the tropical sign in which the day becomes longer than the night, and Cancer the tropical sign in which the day is longest. The six nocturnal signs compose the trigons of Libra and of Capricornus, the signs of the autumnal equinox and the winter solstice.

There is a trace of this first system in Ludw. Maxim. p. 105 6 sq., "Diurnal: Aries, Cancer, Leo, Sagittarius. Nocturnal: Gemini, Libra, Capricorn, Aquarius," where however Scorpius and Pisces are omitted from the diurnal and Taurus and Virgo from the nocturnal signs. The four signs thus omitted, I note, are those immediately adjacent to the equinoctial signs, and they were perhaps called ἐπίκοινα [common/shared]; for the cod. Berol. 173 at C.C.A.G. VII p. 212 17 has a defective list which may be completed thus: "Diurnal are ♈ ♌ ♐ ♋, nocturnal are <♊ add. Boll> ♎ ♑ ♒, common are <♉ add. Boll> ♏ ♍ ♓ (thus I wrote for II)."

The second system (218-220), by which the six consecutive signs from the vernal equinox onwards, Aries Taurus Gemini Cancer Leo Virgo, are diurnal, and the rest, Libra Scorpius Sagittarius Capricornus Aquarius Pisces, nocturnal, is still more evidently built upon the same foundation: the diurnal signs are those in which the day is longer than the night.

C.C.A.G. IV p. 152 18-20 quoted in my note on verse 218.

The third system (221 sq.), which identifies diurnal with masculine and nocturnal with feminine, and so repeats the scheme of verses 150-154, is, like that scheme, Pythagorean and merely numerical: light was conceived to be odd and darkness to be even (Arist. Metaphysics I 5, p. 986 Bekk.).

Ptol. Tetrabiblos p. 9: "Six of the twelve parts (=signs) they assigned to the masculine and diurnal nature, and an equal number to the feminine and nocturnal. And the arrangement was given to them by alternating... the beginning being taken from Aries... the sign of Aries and also the sign of the Claws were considered masculine and diurnal." C.C.A.G. VII p. 212 17 (cod. Vind.): "Diurnal are ♈ ♊ ♌ ♎ ♐ ♒, nocturnal are ♉ ♋ ♍ ♏ ♑ ♓," p. 213 1 sq.: "Masculine are those which we also wrote as diurnal above," 4 sq.: "Feminine and nocturnal," Iohann. Camat. 2373.

In Heph. Theb. I 1 (pp. 46-67) all is confusion: Leo, Virgo, Scorpius, Sagittarius, Capricorn have the epithet diurnal; Aries, Cancer, Aquarius, Pisces nocturnal; Taurus, Gemini, Libra neither.

223-233 Cancer and Pisces are aquatic, Aries Taurus Leo and Scorpius terrestrial, Capricornus and Aquarius betwixt and between; nothing is said of Gemini Virgo and Libra, which