Astronomical/Astrological symbols for other planets' moons

Orbit symbol

Calligraphic version | Fixed-width version

There are astronomical symbols for each of the 9 planets in our solar system, as well as for the Sun, the Moon, and some of the asteroids. However, I have not been able to find any symbols for the moons/satellites of other planets.

Astronomers, as far as I can tell, use the symbol of the planet plus a roman numeral indicating which orbit the moon is in. This is all well and good, but not very interesting or evocative. Astrologers, on the other hand, have no real reason to have separate symbols for the moons, since they are always in effectively the same part of the sky as their planet (when seen from Earth).

As someone who enjoys thinking about possible lifestyles of the future, I imagine a time when the outer planets will be inhabited, or at least have astrologically interesting events happening on them. (I'm not a believer in astrology myself, but find it interesting.) Future astronomers and astrologers may wish to have symbols for the moons of the planet they are inhabiting or orbiting.

I have invented symbols for many of the other moons. My general method is to take some aspect of the planetary symbol and apply it to symbols differentiating the moons, usually the initial of the moon's name in the appropriate writing system. I offer these symbols up to the public domain, for use by future astronomers, future astrologers, and anyone else who's interested.


Mars symbol

Mars

Mars has two moons, Phobos and Deimos. The symbols for them are based on the lower-case versions of the Greek letters Phi and Delta, which begin those two names in the original Greek, with the arrow from Mars's symbol added on.


Phobos symbol
Phobos
Deimos symbol
Deimos

The Jovian planets

The Jovian gas giants each have a large number of moons (at least 13 for Neptune, at least 63 for Jupiter). It's not really feasible to include them all, but some are larger than others. I've chosen an admittedly arbitrary threshold of 10 Zg (1019 kg) and created symbols for any moon larger than that, which lets in Saturn's moon Hyperion but not Jupiter's largest non-Galilean moon Amalthea. This is also near the point at which moons become non-spherical - there are some non-spherical objects above this line, but no spherical ones below.


Jupiter symbol

Jupiter

Jupiter has four "large" moons - the four Galilean moons. For their symbols, the Greek letter beginning their names is combined with the cross at the bottom of the symbol for Jupiter.


Io symbol
Io
Europa symbol
Europa
Ganymede symbol
Ganymede
Callisto symbol
Callisto

Saturn symbol

Saturn

Saturn has 8 "major satellites". (They are all spherical except Hyperion.) From a suggestion by my brother Marc Moskowitz, I've combined the Greek letter beginning their names with Saturn's hook. I've used the lower-case rho instead of the capital for aesthetic reasons. Titan and Tethys both begin with tau, so Titan has a circle around its intersection to symbolize its atmosphere.


Mimas symbol
Mimas
Enceladus symbol
Enceladus
Tethys symbol
Tethys
Dione symbol
Dione
Rhea symbol
Rhea
Titan symbol
Titan
Hyperion symbol
Hyperion
Iapetus symbol
Iapetus

Uranus symbol Uranus_2 symbol

Uranus

Uranus has two symbols, both of which include a circle at the bottom. Its moons are named after characters from English literature. Here are symbols for the 5 major satellites, based on the initial of the moon (from the roman alphabet) combined with the lower circle from the symbol for Uranus. (I've used the empty circle from the "H" symbol - if you prefer the arrow symbol, feel free to add the central dot.)


Miranda symbol
Miranda
Ariel symbol
Ariel
Umbriel symbol
Umbriel
Titania symbol
Titania
Oberon symbol
Oberon

Neptune symbol

Neptune

Neptune has 3 "major" moons - Triton, which is the 7th largest moon in the Solar system, and the non-spherical Nereid (31 Zg) and Proteus (50 Zg). Their symbols combine the Greek letter beginning their names and Neptune's trident.


Proteus symbol
Proteus
Triton symbol
Triton
Nereid symbol
Nereid

The dwarf planets and large TNOs

There are five currently-recognized dwarf planets, three of which are known to have moons. (This is not entirely a coincidence - the presence of moons helps determine mass, which is part of the classification process.) Pluto and Ceres have traditional symbols, and I suggest symbols for Eris, Makemake, and Haumea on my page of symbols for TNOs. There are also a number of large TNOs that are likely to be eventually classified as dwarves, two of which are known to have moons. I have proposed symbols for many of these as well, on that same page. I have designed symbols for all the dwarf planets' and TNOs' moons, based on the traditional symbol or my suggested one.


PLuto symbolPluto symbol

Pluto

Pluto has two symbols, one usually used by astronomers and one usually used by astrologers. The astronomical symbol is a combination of the letters P and L, both for the planet PLuto and in honor of Percival Lowell. The astrological symbol is a circle inside an arc above a cross.

Pluto has five moons: Charon, Nix, Hydra, Kerberos, and Styx. Charon was discovered by James Christy and named to honor his wife Charlene, so a symbol combining C and H is the obvious choice for an astronomical symbol. The astrological symbol uses the floating circle from Pluto and applies it to a sideways crescent, referencing both Charon being a moon and Charon's mythological meaning as a boatman across the river of the dead. (A version of this symbol is apparently already a less common symbol for Pluto.) Nix is either a misspelling of the Greek goddess Nyx, in which case it starts with Nu, or Latin for "snow", which starts with N. Luckily capital Nu and capital N look the same. Hydra begins with Upsilon in Greek. Kerberos and Styx have straightforward symbols involving Kappa and a lowercase Sigma.


CHaron symbol
Charon (astronomical)
NIx symbol
Nix (astronomical)
HYdra symbol
Hydra (astronomical)
KErberos symbol
Kerberos (astronomical)
STyx symbol
Styx (astronomical)
Charon symbol
Charon (astrological)
Nix symbol
Nix (astrological)
Hydra symbol
Hydra (astrological)
Kerberos symbol
Kerberos (astrological)
Styx symbol
Styx (astrological)

Eris symbol

Eris

Eris's symbol is two curvy arrows colliding, so Dysnomia's symbol is two curvy Deltas colliding.


Dysnomia symbol
Dysnomia

Haumea symbol

Haumea

I've taken the two circles of Haumea's symbol and incorporated them into an H and N for Hi'iaka and Namaka.


Hiiaka symbol
Hi'iaka
Namaka symbol
Namaka

Quaoar symbol

Quaoar

I've included Quaoar's "canoe" shape into a watery W or WW for Weywot.


Weywot symbol
Weywot

Orcus symbol

Orcus

Vanth's symbol applies Orcus's circled-tilted-letter motif to the Etruscan character for the V sound.


Vanth symbol
Vanth

Salacia symbol

Salacia

Actaea's symbol applies Salacia's sigma fish-tail to the Greek letter Alpha.


Actaea symbol
Actaea

Smaller versions of the moon images:

Phobos symbol
Phobos
Deimos symbol
Deimos
Io symbol
Io
Europa symbol
Europa
Ganymede symbol
Ganymede
Callisto symbol
Callisto
Mimas symbol
Mimas
Enceladus symbol
Enceladus
Tethys symbol
Tethys
Dione symbol
Dione
Rhea symbol
Rhea
Titan symbol
Titan
Hyperion symbol
Hyperion
Iapetus symbol
Iapetus
Miranda symbol
Miranda
Ariel symbol
Ariel
Umbriel symbol
Umbriel
Titania symbol
Titania
Oberon symbol
Oberon
Proteus symbol
Proteus
Triton symbol
Triton
Nereid symbol
Nereid
CHaron symbol
Charon
NIx symbol
Nix
HYdra symbol
Hydra
KErberos symbol
Kerberos
STyx symbol
Styx
Charon symbol
Charon
Nix symbol
Nix
Hydra symbol
Hydra
Kerberos symbol
Kerberos
Styx symbol
Styx
Dysnomia symbol
Dysnomia
Hiiaka symbol
Hiiaka
Namaka symbol
Namaka
Weywot symbol
Weywot
Vanth symbol
Vanth
Actaea symbol
Actaea

Sightings

Some of these symbols have been used in a series of videos. See the sightings page for details.


To see these symbols in context with other ones, I've created a list of the largest named objects in our solar system, with a symbol by each object. I've also used the Phobos and Deimos symbols in natal charts for the NASA rovers Spirit and Opportunity.


This page and these graphics by Denis Moskowitz. Last modified Wednesday July 3, 2013. The symbols are given to the public domain and may be used freely, copied, redrawn, critiqued, etc. but please don't claim credit for them.


Other new astro symbols