• 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.

  • 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.