• Galileo, Sidereus Nuncius

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    When Galileo observed the belt and sword of Orion the Hunter, and the Pleiades star cluster on the back of Taurus the Bull, the background of night gave way before his eyes: His telescope resolved an astonishing number of unexpected stars never seen before. 

    On one page he shows 36 new stars around the original six of the Pleiades, and on another, 80 new stars near the belt and sword of Orion. What if uncountable stars might exist, much farther away than was previously believed? How plausible would it be for an immense and vastly thick sphere of stars to rotate every 24 hours around a tiny central, stationary Earth?

    “For the Galaxy is nothing else than a congeries of innumerable stars distributed in clusters. To whatever region of it you direct your spyglass, an immense number of stars immediately offer themselves to view, of which very many appear rather large and very conspicuous but the multitude of small ones is truly unfathomable.”
    Galileo, Sidereus Nuncius
    trans. Albert Van Helden (University of Chicago, 1989).

     

  • Bayer, Uranometria

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    First published in Augsburg in 1603, Bayer’s atlas consists of 51 double-page copperplate engravings. Bayer plotted his stars on a coordinate grid with one-degree intervals. His own star catalog, bound at the front of this volume, is based on the star positions of Tycho Brahe. 

    A dark horizontal band runs through all the constellations of the Zodiac, where the planets move against the background of fixed stars.  Bayer depicted the band 8 degrees above and below the ecliptic, or annual path of the Sun. For example, in the constellation of Taurus the Bull, the ecliptic runs across the page in the center of the Zodiac horizontal band.  The Milky Way angles down the left side.

    Bayer labeled the stars with Greek letters, according to their apparent magnitude, so that the brightest star in Taurus, Aldebaran, is alpha-Tauri. This convention is still used today.

    In contrast to Piccolomini, who omitted constellation figures in favor of scientific accuracy, Bayer superimposed constellation figures upon the star maps without compromising positional accuracy. These figures were artfully drawn by Alexander Mair. By fusing science and art, merging true star maps with innovative constellation figures, Bayer inaugurated the golden age of the celestial atlas.

    Bayer’s atlas consists of 51 double-page copperplate engravings, including 2 planispheres, one star map for each of the 48 Ptolemaic constellations, and one map for 12 new constellations of the southern skies reported by 16th-century explorers (cf. the discussion of the southern stars plate in Ridpath Star Tales.)

    The 1603 1st edition printed both sides of the leaves.  In this later edition, the absence of printed text on the back side of each leaf prevented type from showing through on the atlas pages.  Each double-page atlas leaf is attached to a strip of scrap paper that is bound in the gutter, so that the atlas image itself does not disappear down into the fold.

    Bayer showed the star positions as they appear from the Earth (rather than from the outside, as on a celestial globe). However, he sometimes reversed the constellation figures, drawing them as seen from the back, which created potential confusion. For example, the star Rigel, described by Ptolemy as the left foot of Orion, became Orion’s right foot in Bayer’s figure, even though the star pattern remained the same as seen from Earth.

    In the star catalog bound at the front of the OU copy, each star is listed along with its number from Ptolemy’s star catalog, and with the Greek letter assigned to it by Bayer to represent its brightness. Tycho’s star catalog included about 1,000 stars. Bayer incorporated many of these and added about 1,000 of his own, for a total of about 1,700 stars.  A bright circle in the constellation of Cassiopeia shows where a nova appeared in 1572, described by Tycho Brahe.

  • Bode, Uranographia

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    This magnificent atlas fused artistic beauty and scientific precision. Bode, director of the Observatory of the Berlin Academy of Sciences, produced the last of the four major celestial atlases in which artful depictions of constellation figures appear alongside the most up-to-date scientific data. 

    20 large copperplate engravings plot more than 17,000 stars, far more than any previous atlas. Bode included new stars for the southern hemisphere, along with constellations recently invented by Hevelius and Lacaille. 

    Bode depicted more than 100 constellations, compared with 88 officially recognized today. Some which appeared in this atlas for the first time, but are not officially recognized today, include the Cat, the Printing Press, the Montgolfier Balloon, and the Electric Generator. 

    Bode also included 2,500 cloudy patches, or “nebula,” cataloged by William Herschel.

    Planispheres

    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.

    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.

    Earlier, in 1782, Bode published a small-format atlas based on a Paris edition of Flamsteed.

    The four great celestial atlases of Bayer, Hevelius, Flamsteed and Bode were each distinctive in their artistic style as well in their scientific importance. After Bode, this fusion of art and science in celestial atlases ceased, as scientific atlases no longer held room to include artistic constellation figures.

  • Messier, “Catalogue des Nébuleuses et des Amas d’Étoiles”

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    This is the first edition of Messier’s catalog of cloudy spots or “nebulae,” numbered from M1 to M45. The Great Orion Nebula is M42. In 1781, Messier published a final catalog of 103 nebulae, which are now called “Messier objects.”

    Comet watching required an ever more complete mapping of the sky. In multiple articles, Messier traced the routes of comets through various constellations, mapping the nebulae along the way so as not to confuse them with the comets.

    Earlier in this same volume, Messier published an article, with a star map, describing the second comet of 1770-1771, which passed near Orion.

  • Hyginus, Poeticon astronomicon

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    Greek writers like Hesiod and Aratos compiled ancient stories of the constellations, often in poetic form, with memorable instructions for locating bright stars and zodiac constellations. Constellations of the zodiac contain the wandering courses of the planets and the annual path of the Sun. Familiarity with the stars enabled one to coordinate the affairs of life, including agricultural cycles, with the sky at night.

    Hyginus, a Roman poet, conveyed this body of practical knowledge into Latin. Hyginus followed the order and naming of the constellations as listed in the Almagest of Ptolemy (2d century C.E.). Charming constellation figures are hand-colored in this copy. It was printed by Erhard Ratdolt, a renowned early printer of works in astronomy and geometry.

  • Urania’s Mirror

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    Constellation figures, as in this boxed set of 32 constellation cards, make learning the constellation names memorable.  Each card illustrates one or a few constellations. Holes punched in the positions of bright stars allow one to hold any card up to a light and compare the star pattern with the constellation figure.  Urania, the Muse of Astronomy, appears on the cover of the box.   

    The 66 constellations include several no longer recognized today. 

    This is the first edition; subsequent editions include stars outside the boundaries of the featured constellations.

    The creator of the cards remains a mystery.  In a companion book providing a simple introduction to the night sky, Jehoshaphat Aspin explains only that the constellation cards “were designed by a lady.”  (Jehoshaphat Aspin, A Familiar Treatise on Astronomy (London 1825), 2d ed.)

    The constellation figures are based upon the Celestial Atlas of Alexander Jamieson, published in 1822. 

  • Bainbridge, An astronomicall description

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    In this English contribution to the controversy on the comets of 1618, Bainbridge came to a similar conclusion as Oratio Grassi in Italy - that comets move through the heavens beyond the Moon.  

    This book contains the first telescopic observations published in England and the first recorded use of the word “telescope” in English.  

    In this work, Bainbridge also rejected the astrological significance of comets.  He later became the first Savilian Chair of Astronomy at Oxford.