• 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.

  • Coronelli, Celestial Globe Gores

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    Coronelli, a Franciscan theologian and astronomer who worked in both Italy and France, was a founder of modern geography and an influential maker of celestial and terrestrial globes. Makers of globes printed sheets of map sections, called gores, which were then hand-colored, cut out and glued onto a wood and paper-maché base. 

    These 9 gores were part of a set of 24 produced at the request of Coronelli’s Accademia Cosmografica to make a 3.5 foot diameter celestial globe. They were designed by Arnold Deuvez and engraved by Jean-Baptiste Nolin in Paris. The set was a reprint of gores which Coronelli printed in Venice in 1688. At the time, Coronelli’s 1688 globe was the largest and most accurate printed celestial globe. The Latin and French legends distinguish this 1693 Paris reprint from the 1688 originals, which were in Italian.

    These gores are reprints made in 1800 using the original 1693 plates.

    In the Epitome Cosmographica, Coronelli explained how to use celestial and terrestrial globes and his techniques for constructing them. The Epitome describes how Coronelli famously constructed a pair of terrestrial and celestial globes for Louis XIV which measured more than 12 feet in diameter. 

  • 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.

  • Schickard, Astroscopium (1698)

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    Schickard, a friend of Kepler’s, designed this “astroscopium,” a model intermediate between a planisphere and a celestial globe, to calculate the positions of the stars for any day and hour of the year. 

    Schickard also devised a calculating machine to produce astronomical tables according to Kepler’s laws.

    The constellations in Shickard's Astroscopium identify the constellations with biblical characters, in addition to the commonly accepted ancient names.

    Print the plates and you can assemble your own Astroscopium model.