Astronomical symbols
The Byzantine codices in which many Greek papyrus texts were preserved continued and extended the inventory of astronomical symbols.
While they are still commonly used in almanacs and astrological publications, their occurrence in published research and texts on astronomy is relatively infrequent,[4] with some exceptions such as the Sun and Earth symbols appearing in astronomical constants, and certain zodiacal signs used to represent the solstices and equinoxes.
The forms of the symbols that appear in the original papyrus texts of Greek horoscopes are a circle with one ray () for the Sun and a crescent for the Moon.
[11][12][13][14] Symbols for the classical planets appear in many medieval Byzantine codices in which many ancient horoscopes were preserved.
[2] The written symbols for Mercury, Venus, Jupiter, and Saturn have been traced to forms found in late Greek papyrus texts.
Maunder, antecedents of the planetary symbols were used in art to represent the gods associated with the classical planets; Bianchini's planisphere, discovered by Francesco Bianchini in the 18th century, produced in the 2nd century,[27] shows Greek personifications of planetary gods charged with early versions of the planetary symbols: Mercury has a caduceus; Venus has, attached to her necklace, a cord connected to another necklace; Mars, a spear; Jupiter, a staff; Saturn, a scythe; the Sun, a circlet with rays radiating from it; and the Moon, a headdress with a crescent attached.
[28] A diagram in Byzantine astronomer Johannes Kamateros's 12th century Compendium of Astrology shows the Sun represented by the circle with a ray, Jupiter by the letter Zeta (the initial of Zeus, Jupiter's counterpart in Greek mythology), Mars by a shield crossed by a spear, and the remaining classical planets by symbols resembling the modern ones, without the cross-mark at the bottom of the modern versions of the symbols for Mercury and Venus.
According to Maunder, the addition of crosses appears to be "an attempt to give a savour of Christianity to the symbols of the old pagan gods.
[37] Professor James Pillans of the University of Edinburgh defended the name Janus for the new planet, and proposed a key for its symbol.
[34] Meanwhile, German-Russian astronomer Friedrich Georg Wilhelm von Struve presented the name Neptune on December 29, 1846, to the Saint Petersburg Academy of Sciences.
[40] In certain cases where planetary symbols might be used, such as in the headings of tables, the IAU Style Manual permits certain one- and (to disambiguate Mercury and Mars) two-letter abbreviations for the names of the planets.
[47] In a letter to von Zach, discoverer Heinrich Wilhelm Matthäus Olbers (who had discovered and named Pallas) expressed his approval of the proposed symbol, but wished that the handle of the sickle of Ceres had been adorned with a pommel instead of a crossbar, to better differentiate it from the sign of Venus.
Harding, who discovered this asteroid in 1804, proposed the name Juno and the use of a scepter topped with a star as its astronomical symbol.
[52][53] Karl Ludwig Hencke, a German amateur astronomer, discovered the next two asteroids, 5 Astraea (in 1845) and 6 Hebe (in 1847).
[16] Thus the iconic asteroid symbols fell out of use; reference works continued giving them for the next few decades, though they often noted them as being obsolete.
[82] The symbol for 99942 Apophis, a near-Earth asteroid discovered in 2004 that attracted interest when initial observations suggested a significant probability of an Earth impact in 2029 (a possibility since eliminated), is much later.
Denis Moskowitz, a software engineer in Massachusetts,[94] proposed astronomical symbols for the dwarf planets Quaoar, Sedna, Orcus, Haumea, Eris, Makemake, and Gonggong.
[94] Therefore, symbols mentioned in the Unicode proposal for Haumea, Makemake, Gonggong, Quaoar, and Orcus have been shown below to fill out the list of named TNOs down to 600 km diameter, even though not all of them are actually attested in astronomical use.
(Grundy et al. suggest 600 to 700 km diameter as a speculative upper limit for a trans-Neptunian object to retain substantial pore space.
Depending on context, a zodiac symbol may denote either a constellation, or a point or interval on the ecliptic plane.
Ophiuchus has been proposed as a thirteenth sign of the zodiac by astrologer Walter Berg in 1995, who gave it a symbol that has become popular in Japan.
[3] In describing the Keplerian elements of an orbit, ☊ is sometimes used to denote the ecliptic longitude of the ascending node, although it is more common to use Ω (capital omega, and inverted ℧), which were originally typographical substitutes for the astronomical symbols.
