• Car - Carina the Keel of Argo Navis

    Size

    34 of 88

    Astronomical Regions

    Intro and Visual description

    Locate Canopus by drawing a line from the easternmost star of Orion’s belt down through Rigel, Orion’s left foot. Canopus lies about twice as far from Orion’s belt as Sirius.

    Between Canopus and the south pole lies the Large Magellenic Cloud (LMC), located in the constellation Dorado the Swordfish.

    Between Canopus and Crux are the False Cross (nearer Canopus, shared by Carina and Vela) and the Diamond Cross (nearer Crux, in Carina). These are fainter than Crux and were once part of Argo Navis.

  • Oct - Octans the Octant

    IAU Constellation

    Size

    50 of 88

    Astronomical Regions

    Intro and Visual description

    Octans the Octant is devoid of bright stars, but three faint stars (not numbered by brightness) make a small triangle.

    The south celestial pole actually lies within Octans. No RA (visible anytime).  

    The nearest easy-to-spot star to the south pole is Beta-Hydri in Hydrus the Little Snake. No brighter star than Achernar (alpha-Eridani) is closer to the south celestial pole, which lies midway between Achernar (Eridanus) and Crux.

  • 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.

  • Bayer, Uranometria (1661): Southern stars

    Image

    Clockwise from top center: Pavo, Apis, Triangulum Australe, Musca, Chamaeleon, Volans, Dorado, Nubecula Major, Phoenix (left margin), Grus (outside upper left), Indus (left of Pavo), Tucana (below Grus), Hydrus (below Tucana, near center), and Nubecula Minor (just under Hydrus).