The following fictional celestial bodies figure prominently in the Cthulhu Mythos stories of H. P. Lovecraft and other writers. Many of these astronomical bodies have parallels in the real universe, but are often renamed in the mythos and given fictitious characteristics. In addition to the celestial places created by Lovecraft, the mythos draws from a number of other sources, including the works of August Derleth, Ramsey Campbell, Lin Carter, Brian Lumley, and Clark Ashton Smith.
- Name. The name of the celestial body appears first.
- Description. A brief description follows.
- References. Lastly, the stories in which the celestial body makes a significant appearance or otherwise receives important mention appear below the description. A simple two-letter code is used—the key to the codes is found here. If a code appears in bold, this means that the story introduces the celestial body.
A planet that revolves around seven stars beyond Xoth. It is inhabited by metallic brains, wise with the ultimate secrets of the universe. According to Friedrich von Junzt's Unaussprechlichen Kulten, Nyarlathotep dwells or is imprisoned on this world (though other legends differ in this regard).
Aldebaran is the star of the Great Old One Hastur.
Double star mentioned by H.P. Lovecraft as sidereal place of a demonic shining entity made of light. The same star is also described in other Mythos stories as a planetary system host (See Ymar).
Arcturus is the star from which came Zhar and his "twin" Lloigor. Also Nyogtha is related to this star.
Celaeno is one of the seven stars of the Pleiades. On its fourth planet is the Great Library of Celaeno, which houses stone tablets containing secrets stolen from the Great Old Ones and Elder Gods. Professor Laban Shrewsbury spent some time here, transcribing the library's knowledge in his notebook—a manuscript that would later be known as the Celaeno Fragments.
Corona Borealis 
Sky field mentioned in H.P. Lovecraft's "Hypnos" (1922).
The Hyperborean name for the planet Saturn is Cykranosh. It was the home of the god Tsathoggua before he came to Earth, though several of his relatives, including his uncle, Hziulquoigmnzhah, still dwell there.
Fomalhaut is the main star of Piscis Austrinus, a bright white-blue main sequence star. It is orbited by a planet where the Great Old One Aphoom-Zhah was born and near lies the star Korvaz, where the Great Old One Cthugha is imprisoned.
Glyu-Uho (or Glyu-Vho or K'Lu-Vho) is the name for Betelgeuse in Naacal (the language of Mu), and is the star where the Elder Gods came from to battle the Great Old Ones (though it may actually be the place where a gateway leads to Elysia, the dimension where the Elder Gods are thought to live).
LS, LT, RB, S4, TA, TP
Haddath (also Haddoth or perhaps Urakhu) is a fiery planet, possibly found near the "eye" of the constellation Hydra, and is believed to be inhabited by the chthonians. Shub-Niggurath is thought to have once dwelt here.
Hyades is the sky field where the city of Carcosa and its planet are located. The planet-host star of Carcosa is described as "twin Suns", making it then a Solar-type binary star.
A distant ammonia planet orbiting a dying star, homeworld of the Great Old One Kaalut.
A star located near Fomalhaut (likely TW Piscis Austrini) where the Great Old One Cthugha is imprisoned.
A jungle planet orbiting a binary star system, composed of a green star and a dead one (likely a black hole), likely matching with Yifne and Baalblo. Kr’llyand was the homeworld of the plant-like Great Old One Ei'lor, which once was a dead star like its neighbor Mirkalu, but after Elder Gods banished Ei'lor there, the seed of the Great Old One was sown and spread fertilizing the dead planet.
Ktynga (or Norby's comet) is the name of a bluish comet that is currently near the star Arcturus. The comet is unusually hot and has strange properties, such as the ability to travel faster than light.
On the surface of the comet is a huge building wherein dwells the being Fthaggua and his servants, the fire vampires. Fthaggua and his minions can guide the comet to travel between the stars, and will visit our solar system four centuries from now.
A dark-litten and mist-shrouded planet from whence comes N'rath-Gol, a minion of Nyarlathotep.
A mysterious celestial body located past Yuggoth (or Pluto?) on the edge of the solar system.
Kythanil (or Kythamil or Kthymil) is a double planet orbiting the star Arcturus and is the place were Tsathoggua's formless spawn came from.
The planet Uranus. It is inhabited by metallic, cube-shaped beings with multiple legs. These creatures worship a minor deity known as L'rog'g (possibly another aspect of Nyarlathotep), whose rituals require a yearly sacrifice in the form of the excising of the legs from a native.
When the Insects from Shaggai (the Shan) arrived, the natives of L'gy'hx initially tolerated them and allowed them to build a huge city. After two centuries, the natives even came to see the Shan as co-rulers of the planet. In time, many Shan eschewed the veneration of Azathoth and began to worship the L'gy'hx deity L'rog'g. But when some natives of L'gy'hx likewise turned to the worship of Azathoth, the event prompted the priests of L'rog'g to start an inquisition, inflicting gruesome punishments on the heretics. Relations with the Shan soured quickly as a result, and the priests of L'rog'g demanded that all temples of Azathoth be removed from L'gy'hx. A small group of the Shan, still faithful to the Azathoth sect, left L'gy'hx, teleporting themselves and their deity's temple to the planet Earth.
A dead planet or failed star (a brown dwarf) mentioned in the Ei'lor Fronds as neighbor of Kr’llyand.
Dark planet inhabited by crystalline beings and the dwelling place of the Great Old One Q'yth-az. The Nug-Soth of Yaddith journeyed to this world in hopes of finding a magical formula that would defeat the Dholes.
Star Pherkard (or Gamma Ursae Minoris) is mentioned as the stellar abode of the flaming Outer God Yomagn'tho.
Stellar regions where star Celaeno is located. Pleiades are also mentioned as the stellar abode of the Great Old One Gtuhanai and the mysterious alien race of the Aartna too.
FN, HC, HT, RB, US, WS
The second star of Orion constellation Rigel is mentioned by August Derleth as one of the sidereal realms of the Elder Gods along with Betelgeuse.
Shaggai (or Chag-Hai) is a planet orbiting twin green suns and is the homeworld of the Shan, or Insects from Shaggai. Lovecraft first mentioned Shaggai twice in The Haunter of the Dark, but gave no details, save that it was further out in the cosmos than Yuggoth.
The Shan's planet was destroyed eight centuries ago, possibly by Ghroth the Harbinger. The being known only as The Worm that Gnaws in the Night also resides here.
Shonhi (also Stronti) is a transgalactic world frequented by the denizens of Yaddith. It has been visited by the Great Old One Yig and orbits three suns.
A planet where the Insects from Shaggai dwelt for a while. They initially believed the planet was uninhabited; but when their slaves began disappearing, they soon discovered the terrible truth. They left shortly thereafter.
A huge planet that broke apart to form the asteroid belt. According to the G'harne Fragments, the event was caused by a "seed of Azathoth".
A mysterious planet believed to be part of our solar system, though the predominant view places it in a binary star system near Baalblo (a dark star, either a brown dwarf or more likely a black hole) and its companion Yifne (a green sun). The being Glaaki is believed to have visited this world en route to Earth.
BS, FP, IL, MV, MY, PW, RV
Trifid Nebula 
The Trifid Nebula is mentioned as the homeworld of the mysterious Harlequin character featuring in Walter C. DeBill jr.'s "He Who Comes at the Noontime" (2006).
A planet in the "twenty-third nebula" and the supposed birthplace of Great Cthulhu.
The black hole home of the Outer God Haiogh-Yai. It is orbited by a dark planet hosting the block city of Thalu, homeworld of the Voorlak, lizard to leech-like servants of the Outer God.
World of Seven Suns 
Possibly a planet near Fomalhaut according to some writers. Its inhabitants created seven artificial suns to replace their dying natural sun. Lovecraft said that Nyarlathotep dwells on the World of the Seven Suns, but he makes no connection with Fomalhaut.
Others connect the Seven Suns to the seven stars of the Pleiades, the Hyades, or possibly Ursa Major.
A putative Solar System planet located millennia ago in the Main Asteroid Belt and destroyed by "warring forces from Yuggoth and Shaggai".
A dark star, homeworld of the Zorkai, bat-winged ravenous horrors which serve the Great Old One Hastur.
A distant galaxy and the dwelling place of the Great Old One Zathog.
The sister planet of Shaggai. The Shan conquered this world and enslaved its native inhabitants, a race of carnivorous monsters. When Shaggai was destroyed, the Shan joined their brethren here and remained for some time.
[T]he spawn of Cthulhu ... came down from remote and ultra-telluric Xoth, the dim green double star that glitters like a daemonic eye in the blackness beyond Abbith.
—Lin Carter, "Out of the Ages"
Xoth (or Zoth) is the green binary star where Cthulhu and his ilk once lived before coming to earth. According to the Xothic legend cycle, it is where Cthulhu mated with Idh-yaa to beget Ghatanothoa, Ythogtha, and Zoth-Ommog.
Xoth is also the native home of Ycnágnnisssz and Zstylzhemghi, and was the temporary home of the latter's "husband", Ghisguth, and their progeny, the infant Tsathoggua. Tsathoggua later went to live on Yuggoth. Afterward, he fled to Cykranosh to escape Cxaxukluth's cannibalistic eating habits.
Xoth may be the star Sirius, since "Xoth" is similar to "Sothis", the Egyptian name for the star. However, it is more likely that Xoth coincides with the star "Zoth" in Smith's writings.
Yaddith is a distant planet that orbits five suns and is itself orbited by five moons. Yaddith is located thousands of light years from the Sun, near the star Deneb. Aeons ago it was inhabited by the Nug-Soth, creatures with traits similar to mammals, reptiles, and insects. The Nug-Soth sought a way to prevent the destruction of their planet's crust by the Dholes, but to no avail. Eventually, the Dholes overwhelmed them and destroyed the Nug-Soth's civilization. Survivors of the catastrophe escaped, however, and hid on various planets. Life on Yaddith amongst the Nug-Soth and the Dholes that threatened them was first described in detail in Through the Gates of the Silver Key as Randolph Carter is stranded there for hundreds of years while sharing the body of Zkauba the wizard, though Lovecraft did not name the race that inhabited the planet.
Robert M. Price's short story "Saucers from Yaddith" (1984) hints that Nug-Soth scientists have appeared on Earth performing various experiments on humans—some relatively harmless (such as changing a man's blood type from B to A), some rather bizarre (two brothers in medieval Germany claimed that an "angel" had switched their hands and eyes), and others utterly horrific or disgusting.
AY, DR, HD, TG, HG, VI
Yaksh is the planet Neptune and is inhabited by strange fungous beings. Hziulquoigmnzhah dwelt here for a while after fleeing Yuggoth to escape Cxaxukluth's cannibalistic urges. Hziulquoigmnzhah was evidently worshipped by the Yakshians, but he soon tired of their venerations and moved to Cykranosh.
Planet with three moons that orbits Betelgeuse in the mysterious Gray Gulf of Yarnak. The now-deserted city of Bel Yarnak is on its surface. The world may have been the one-time home of the Great Old One Mnomquah. The fabled city of Bel-Yarnak is located here.
A planet in a distant galaxy. It is inhabited by a race of technologically-advanced beings that resemble huge centipedes that are slightly larger than a human. The populace worships an entity known as Juk-Shabb, which appears as a glowing, color-shifting orb. Very little is known about this deity other than it is telepathic and is greatly revered by the denizens of Yekub.
The Yekubians destroyed all intelligent life in the galaxy where they dwelt and sought to extend their influence throughout the universe. As part of their grand scheme, they sent out cube-shaped probes that could effect a mind-swap with any intelligent creature who found one. In this way, Yekubian agents could infiltrate the finder's world. One such cube landed on the Earth during the reign of the Great Race of Yith. When several of its members were taken over, the Yithians realized the danger of the cube and sequestered it under heavy guard. Eventually, however, the cube was lost.
A giant ocean planet orbiting a blue-green oval star (somehow similar for oblateness to Achernar), homeworld of the Great Old One Yorith. Yilla is also orbited by Xithor, an airless gold-ringed moon whose hollow mantle is inhabited by the sentient dwarfish race known as the Lloervs, able to capture the souls of dreamers.
The original homeworld of the Great Race of Yith, according to the Eltdown Shards. It is described as a "black, aeon-dead orb in far space" ("The Shadow out of Time", Lovecraft). Its actual location is a mystery. Some scholars place it in our own solar system, just beyond Pluto; others say it is the fourth of the five planets that orbit a dim dark star named Ogntlach. Yith is said to have a thin atmosphere and seas heated by geothermal energy.
The Hyperborean name for the planet Jupiter. Noctosa & Nctolhu are imprisoned here.
A planet in the same star cluster as Abbith, Xoth, and Zaoth. In Lin Carter's The Feaster from the Stars: The History of Yzduggor the Eremite, Ymar is said to orbit the star Algol and to be the homeworld of the Great Old One Zvilpogghua, an offspring of Tsathoggua (See Algol).
Yuggoth (or Iukkoth) is the dwarf planet Pluto. It is home to the Mi-Go, a race of fungi-crustacean of Lovecraft's invention. In Richar A. Lupoff's Discovery of the Ghooric Zone—March 15, 2337, it alternately appears as an enormous planet that orbits on the rim of the solar system, coinciding with the hypothetical brown dwarf Nemesis or the putative planet Tyche.
DE, DZ, FG, FY, GC, HD, HM, HW, IL, MY, OE, PF, SX, TA, TG, WD
A planet near Xoth. It is home to metal brains and houses a great library of Yuggothian books. After Yaddith was destroyed by the Dholes, several survivors of the catastrophe fled here.
Remote sideral place mentioned as the homeworld of the Great Old One Quyagen.
- Harms, Daniel (1998). The Encyclopedia Cthulhiana (2nd ed.). Oakland, CA: Chaosium. ISBN 1-56882-119-0.
- Joshi, S. T. (1989). "Lovecraft's Other Planets". Selected Papers on Lovecraft (1st printing ed.). West Warwick, RI: Necronomicon Press. ISBN 0-940884-23-2.
- Price, Robert M. (Candlemas 1984). "Brian Lumley—Reanimator". Crypt of Cthulhu #19: A Pulp Thriller and Theological Journal 3 (3). Robert M. Price (ed.), Bloomfield, NJ: Cryptic Publications. URL accessed on February 27, 2006.
- ^ H.P. Lovecraft, "Beyond the Wall of Sleep" (1919).
- ^ Lovecraft never used "Glyu-Uho" in his own fiction, but did suggest it to Derleth. (Harms, "Glyu-Uho", The Encyclopedia Cthulhiana, p. 122.)
- ^ Robert W. Chambers, The Repairer of Reputations.
- ^ Daniel Harms, Encyclopaedia Cthulhiana, p. 57.
- ^ James Ambuehl, The Star-Seed.
- ^ Price, "Brian Lumley—Reanimator". Price writes: "Kythanil [is] an alien planet mentioned in Lovecraft's portion of 'Through the Gates of the Silver Key' (though only in manuscript — it is misprinted as 'Kythamil' in the printed texts)."
- ^ J.B. Lee, "Forces of Change" (1999).
- ^ Though the name appears as "Stronti" in Lin Carter's fiction, it is spelled "Shonhi" in the original manuscripts for "Through the Gates of the Silver Key" (1934, Lovecraft and E. Hoffman Price). (Harms, "Shonhi", The Encyclopedia Cthulhiana, p. 274.)
- ^ James Ambuehl's "The Snake God of Shonhi" (1998)
- ^ Daniel Harms thinks that the World of the Seven Suns may refer to the Big Dipper because of its association with Tezcatlipoca, Set, and Zeus. (Harms, The Encyclopedia Cthulhiana, p. 331.)
- ^ J.B. Lee "Genuine Article" (1998).
- ^ The first mention of Yaddith was in the "Alienation" sonnet of Lovecraft's poem Fungi from Yuggoth (1929–30). The planet next appeared in Lovecraft's short story collaboration with E. Hoffman Price "Through the Gates of the Silver Key" (1932–33), though the sub-plot about Yaddith was entirely Lovecraft's idea. In Lovecraft's revision of Hazel Heald's "Out of the Aeons" (1933), Yaddith is suggested by the name of the mountain that is the dwelling place of Ghatanothoa: Yaddith-Gho. Finally, in Lovecraft's "The Haunter of the Dark" (1935), the doomed character Robert Blake swears an oath to the planet: "Everything depends on lightning. Yaddith grant it will keep up!"; as does Alonzo Typer in Lovecraft's revision of William Lumley's "The Diary of Alonzo Typer" (1935): "And may the Lords of Yaddith succor me". (Joshi, "Lovecraft's Other Planets", Selected Papers on Lovecraft, pp. 39–40; all dates are the year written.)
- ^ Not to be confused with James Ambuehl's Great Old One Y'lla. See Cthulhu Mythos deities.
- ^ Walter C. DeBill jr., "The Horror From Yith", in Black Sutra, p. 98.
- ^ Harms, "Yith", The Encyclopedia Cthulhiana, p. 344.
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