• Cep - Cepheus the King of Ethiopia

    Size

    27 of 88

    Astronomical Regions

    Intro and Visual description

    The Ethiopian king, Cepheus (SEE-fee-us), is a circumpolar constellation that sits atop the Milky Way on a throne near his queen Cassiopeia. The legs and seat of his throne make a rough square on the Ursa Major side of Cassiopeia. Cepheus looks like a house (or throne) sitting on the Milky Way. The back of the seat comes to a point at the top above his head.

  • UMi - Ursa Minor the Little Bear

    Size

    56 of 88

    Astronomical Regions

    Intro and Visual description

    Use the pointer stars of the Big Dipper to find Polaris, the tip of Ursa Minor’s tail. The whole sky seems to rotate around Polaris once a day, since it is located near the north celestial pole. The two other bright stars of Ursa Minor represent the far edge of its dipper, and lie nearer to the Big Dipper.

  • The Little Dipper

    Asterism Visual Appearance

    The Big and Little Dippers pour into each other, just as the Big Bear and the Little Bear ceaselessly turn around and around the northern sky. The Guard stars of the Little Dipper protect Polaris from the Great Bear, just in case he might try to catch the North Star for himself.

  • Bode (1801), plate 2: Libra Planisphere

    Image

    Uranographia Tab II. Stellatum Hemisphaeri um Librae

    Bode included two planisphere plates. They are not southern and northern hemispheres; each one has Polaris at the top and the south pole at the bottom. Each one is centered upon an equinox point (where the ecliptic or path of the Sun and the celestial equator intersect). The March equinox point was in Aries in antiquity; by Bode’s time, due to the precession of the equinoxes, it had shifted to Pisces. The September equinox point was in Libra in antiquity; by Bode’s time it had shifted to Virgo.  Bode titled the plates as the Aries and Libra planispheres.

    The Libra planisphere, centered on the September equinox in Virgo, includes these constellations, among others, which appear high overhead in the night skies of spring:

    Equatorial:  Ophiuchus, Serpens, Libra, Virgo, Crater, Corvis, Hydra, Sextans, Leo, Cancer, Monoceros.

    Northern:  Hercules, Quadrans Muralis, Bootes, Canes Venatici, Ursa Major, Telescopium Herschelii, Gemini, Lynx, Ursa Minor.

    Southern:  Scorpius, Tubus Astronomicus, Lupus, Centaurus, Apis, Chameleon, Crux, Argo Navis, Robur Caroli II, Circinus (sector compass), Canis Major, Pixis Nautica (magnetic compass), Machina Pneumatica (air pump), Officina Typographica (printing press).

    In September, the Libra-Virgo equinox (the center of the Libra plate) is traveling with the Sun, rising in the east in the morning and setting in the west in the evening.  Imagine the center of the planisphere has the Sun pinned to it for that day, and that’s how it would move across the sky. Therefore the constellations near the center of this planisphere are invisible in the daytime sky at that time unless there is a solar eclipse.  They would be visible directly opposite the Sun at the March equinox.