• Aur - Auriga the Charioteer

    IAU Constellation

    Size

    21 of 88

    Astronomical Regions

    Intro and Visual description

    Auriga lies in the Milky Way, with many binocular and telescopic objects, between Gemini, Perseus and Taurus, at the top of the Winter Hexagon. Auriga looks like a pentagon, if one includes Alnath, which is also the tip of one of Taurus the Bull’s horns (Alnath was once Gamma-Aurigae, but is now officially Beta-Tauri).

  • Gem - Gemini the Twins

    IAU Constellation

    Size

    30 of 88

    Astronomical Regions

    Intro and Visual description

    Look for the two bright stars, Castor and Pollux, which form one vertex of the Winter Hexagon. Castor is closer to Capella, in Auriga on the north; and Pollus is closer to Procyon, in Canis Minor on the south. Cancer and Leo lie to the east.

    The Geminids meteor shower occurs around October 19.

  • Lyn - Lynx

    IAU Constellation

    Size

    28 of 88

    Astronomical Regions

    Intro and Visual description

    Lying between Ursa Major and Gemini, the Lynx is a row of very dim stars silhouetting its crouched outline. From antiquity the lynx was renowned for its keen night vision. Hevelius created this constellation in 1690, noting that one needs the eyes of a lynx to see it.

  • UMa - Ursa Major the Big Bear

    Size

    3 of 88

    Astronomical Regions

    Intro and Visual description

    Ursa Major or the Big Bear is the third largest of the 88 constellations. Seven stars form a familiar group of stars, or an "asterism" within the constellation. In America they are called the "Big Dipper" or "Drinking Gourd," and in Britain the "Plough" or the "Wain." The Big Dipper is one of the most easily recognizable groups of stars in the sky. It is referred to as circumpolar because it never completely sets below the horizon, but is visible in northern skies year-round.

    The Big Dipper.

    Hubble Deep Field

  • Telescopium Herschelii

    Asterism Origin and History

    Named by Maximilian Hell, S.J., in honor of William Herschel’s discovery of Uranus in this region of the sky in 1781.

  • 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.