• Dor - Dorado the Swordfish

    IAU Constellation

    Size

    72 of 88

    Astronomical Regions

    Intro and Visual description

    Dorado the Swordfish is a small and obscure but very interesting constellation. It contains the Large Magellenic Cloud (LMC) and the only recent naked-eye supernova. In addition, the south ecliptic pole is located about where the "eye" of the fish would be. The Large and Small Magellenic Clouds are bright enough to be visible even in Moonlight.

  • Eri - Eridanus the River

    IAU Constellation

    Size

    6 of 88

    Astronomical Regions

    Intro and Visual description

    The River Eridanus flows northward (like the Nile) from the bright star Achernar (Arabic for "End of the River") to Kursa (beta-Eridani) near Rigel in Orion. Eridanus is the longest (not largest) constellation, spanning over 50 degrees of declination, and its many faint stars glitter like reflecting light off the surface of its waves.

  • Bode (1801), Plate 1: Aries Planisphere

    Image

    Uranographia Tab I. Stellatum Hemisphaeri um Arietis

    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 Aries planisphere, centered on the March equinox in Pisces, includes these constellations, among others, which appear high overhead in the night skies of autumn:

    Equatorial:  Orion, Taurus, Harpa Georgii, Cetus, Aries, Pisces, Pegasus, Aquarius, Aquila, Scutum.

    Northern:  Auriga, Perseus, Andromeda, Cassiopeia, Draco, Honores Frederici, Cepheus, Cygnus, Lyra.

    Southern:  Eridanus, Apparatus Chemicus, Machina Electrica, Apparatus Sculptoris, Horologium, Toucan, Phoenix, Grus, Indus, Pavo, Tubus Astronomicus, Octans Nautica, Microscopium, Sagittarius, Globus Aerostatic.

    In March, the Aries-Pisces equinox (the center of the Aries planisphere) is traveling with the Sun, rising in the east in the mornings and setting in the west in the evenings. 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 September equinox.