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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Astronomical symbols | 3/3 | https://en.wikipedia.org/wiki/Astronomical_symbols | reference | science, encyclopedia | 2026-05-05T08:26:55.281815+00:00 | kb-cron |
All these symbols are rare or obsolete in modern astronomy, though NASA has used Ceres' symbol when describing the dwarf planets, and Psyche's symbol may have influenced the design of the insignia for the Psyche mission. The major use of symbols for minor planets today is by astrologers, who have invented symbols for many more objects, though they sometimes use symbols that differ from the historical symbols for the same bodies. 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. It was designed by Denis Moskowitz, who also designed many of the dwarf-planet symbols, at a time when asteroid symbols had become extremely rare in astronomy. Nonetheless, its inclusion of a star is meant to recall the 19th-century asteroid symbols.
=== Asteroid table ===
== Trans-Neptunian objects == Pluto's name and symbol were announced by the discoverers on May 1, 1930. The symbol, a monogram of the letters PL, could be interpreted to stand for Pluto or for Percival Lowell, the astronomer who initiated Lowell Observatory's search for a planet beyond the orbit of Neptune. Pluto has an alternative symbol consisting of an orb over Pluto's bident: it is more common in astrology than astronomy, and was popularised by the astrologer Paul Clancy, but has been used by NASA to refer to Pluto as a dwarf planet. There are a few other astrological symbols for Pluto that are used locally. Pluto also had the IAU abbreviation P when it was considered the ninth planet. The other large trans-Neptunian objects were only discovered around the dawn of the 21st century. They were not generally thought to be planets on their discovery, and planetary symbols had in any case mostly fallen out of use among astronomers by then. Denis Moskowitz, a software engineer in Massachusetts, proposed astronomical symbols for the dwarf planets Quaoar, Sedna, Orcus, Haumea, Eris, Makemake, and Gonggong. These symbols are somewhat standard among astrologers (e.g. in the program Astrolog), which is where planetary symbols are most used today. Moskowitz has also proposed symbols for Varuna, Ixion, and Salacia, and others have done so for additional TNOs, but there is little consistency between sources. NASA has used Moskowitz's symbols for Haumea, Makemake, and Eris in an astronomical context, and Unicode labels the symbols for Haumea, Makemake, Gonggong, Quaoar, and Orcus (added to Unicode in 2022) as "astronomy symbols".
== Zodiac and other constellations ==
The zodiac symbols have several astronomical interpretations. Depending on context, a zodiac symbol may denote either a constellation, or a point or interval on the ecliptic plane. Lists of astronomical phenomena published by almanacs sometimes included conjunctions of stars and planets or the Moon; rather than print the full name of the star, a Greek letter and the symbol for the constellation of the star was sometimes used instead. The ecliptic was sometimes divided into 12 signs, each subdivided into 30 degrees, and the sign component of ecliptic longitude was expressed either with a number from 0 to 11. or with the corresponding zodiacal symbol. In modern astronomical writing, all the constellations, including the 12 of the zodiac, have dedicated three-letter abbreviations, which specifically refer to constellations rather than signs. The zodiac symbols are also sometimes used to represent points on the ecliptic, particularly the solstices and equinoxes. Each symbol is taken to represent the "first point" of each sign, rather than the place in the visible constellation where the alignment is observed. Thus, ♈︎ the symbol for Aries, represents the March equinox; ♋︎, for Cancer, the June solstice; ♎︎, for Libra, the September equinox; and ♑︎, for Capricorn, the December solstice. Although the use of astrological sign symbols is rare, the particular symbol ♈︎ for Aries, is an exception; it is commonly used in modern astronomy to represent the location of the (slowly) moving reference point for the ecliptic and equatorial celestial coordinate systems.
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.
None of the constellations have official symbols. However, in addition to the zodiac, occasional symbols for other modern constellations, as well as older constellations that occur in modern nomenclature, have appeared in publication. The symbols below were devised by Denis Moskowitz (except those for the 13 constellations already listed above).
== Other == Symbols for aspects and nodes appear in medieval texts, although medieval and modern usage of the node symbols differ; the modern ascending node symbol (☊) formerly stood for the descending node, and the modern descending node symbol (☋) was used for the ascending node. 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. The symbols for aspects first appear in Byzantine codices. Of the symbols for the five Ptolemaic aspects, only the three displayed here — for conjunction, opposition, and quadrature — are used in astronomy. Symbols for a comet (☄) and a fixed star () have been used in published astronomical observations of comets. In tables of these observations, ☄ stood for the comet being discussed and for the star of comparison relative to which measurements of the comet's position were made.
Meteor showers also have limited use of astronomical symbols in the literature, designed by Denis Moskowitz. They are based on the parent constellation symbols, with letters included to disambiguate the Aquariids and Taurids.
For planetary transits of Mercury and Venus, Moskowitz proposed overlaying the respective planetary symbol on that of the Sun, extending the crossbar into an arrow: (Mercury), (Venus). This also has some limited use. Limited use can also be found of Moskowitz's symbol for Halley's Comet, : it is simply the standard comet symbol with an H.
== See also ==
Astrological symbols Alchemical symbols List of common astronomy symbols Maya calendar for the logograms used in Maya astronomy Solar symbol Zodiac
== Footnotes ==
== References ==