“Then Hallowe’en drew near, and the settlers planned another frolic—this time, had they but known it, of a lineage older than even agriculture; the dread Witch-Sabbath of the primal pre-Aryans, kept alive through ages in the midnight blackness of secret woods, and still hinting at vague terrors under its latter-day mask of comedy and lightness.”

— H.P. Lovecraft, “The Curse of Yig”

H.P. Lovecraft had a huge sweet tooth and a morbid streak a mile wide, so of course he must have loved Halloween. His wizardly characters do, too; they make endless Halloween plans that range from kidnapping to time-shaping to world-ending. I count seven cases of Halloween ceremonies (or crimes, or both) in Lovecraft, which seemingly depend on this liminal time for their effect. In “The Dunwich Horror,” the Whateleys commune with Yog-Sothoth “on Hallowe’en” with bonfires on Sentinel Hill. In “The Man of Stone,” the sorcerer “Mad Dan” Morris attempts to sacrifice the Black Goat “at Hallow Eve” and to perform “the Great Rite that would open the gate.” Although in “Dreams in the Witch House” Walter Gilman meets Nyarlathotep at the infant-sacrificing Black Mass on Walpurgisnacht, both Brown Jenkin and “childish cries” manifest “near Hallowmass” as well.

The titular “Very Old Folk” plot their ceremonies for “the first night before the kalends of November” (October 31). The Cthulhu cult in the bayou south of New Orleans kidnapped their victims the night before November 1, 1907, i.e., on October 31. In both of those stories and “Dreams in the Witch House,” the holiday requires human sacrifice: spirit or energy sent through the gate even as the dead mass to travel the other way on All Souls’ Night (November 2). Even the gods themselves are constrained by the calendar: In “The Curse of Yig,” the Lord of Serpents sends “his monstrous children on “All-Hallows’ Night” (technically November 1). And finally, Joseph Curwen’s spell to manipulate fate (and Yog-Sothoth?) must be intoned on May 3 and October 31, or as the ancient wizard put it himself: “This Verse repeate eache Roodemas and Hallow’s Eve; and ye Thing will breede in ye Outside Spheres.”

“Not a breath of the strange grey gods of change
   That tore from the past its own
Can quicken this hour, when a spectral power
   Spreads sleep o’er the cosmic throne,
   And looses the vast unknown.”

— H.P. Lovecraft, “Hallowe’en in a Suburb” (1926)

But why would cosmic forces such as Yog-Sothoth, Cthulhu, and Nyarlathotep care about Halloween? The arbitrary quartering of the northern hemisphere’s calendar is just that, and questions of goat-breeding time, winter wheat harvest, or even the returning dead should seem irrelevant to the Great Old Ones. Halloween isn’t a holiday to these forces, it’s a marker, a regular shift in the curves and angles of Euclidean space-time. Lovecraft’s narrator L. Caelius Rufus gives us the clue in “The Very Old Folk”: “The whole cohort now remained at a standstill, and as the torches faded I watched what I thought were fantastic shadows outlined in the sky by the spectral luminosity of the Via Lactea as it flowed through Perseus, Cassiopeia, Cepheus, and Cygnus.”

Cetus, by Johannes Hevelius (1690)

It’s not the earthly dead that matter on Halloween. It’s the stars, which perhaps almost come right that night. The Pleiades, for instance, rise in the east in October and November, and are directly overhead at midnight on November 21. But twelve hundred years or so ago (call it the 9th century), they were overhead at midnight on October 31 — more than enough reason, say people who like precession no more than I do, and accurate chronology much less, for the Druids (or whoever) to mark that date as Samhain. The Pleiades thus represent the dead, a cluster of dim stars (some still invisible to all but the best Sight) brightening briefly as they return.

What else can we see in the skies just before “the Kalends of November,” then? In Lovecraftian sky lore, we can take note of Algol, the “Demon-Star” from “Beyond the Wall of Sleep.” An angry red variable, Ptolemy identified it (based on much older tradition) as the eye in the head of Medusa wielded by Perseus. But Algol is only one of four variable stars all in the Halloween sky, all in constellations associated with the myth of Perseus: Delta Cephei, Gamma Cassiopiae, and Omicron Ceti, also called Mira, which falls just on the sky’s meridian at midnight. Being variable stars, they make admirable keys to the lock of dimensions, and perhaps their shifting wavelengths just happen to combine or resonate on Halloween: the stars aren’t right that night, but they’re less wrong than on any other date.

Cepheus and Cassiopeia are Andromeda’s parents, Algol is Perseus’ weapon, and Cetus … Cetus is a giant sea monster turned to stone by Medusa’s head. The name “Cetus” comes from the Greek ketos, meaning “sea monster” or, intriguingly, “abyss.” Its further etymology is unknown, but we do have that C-t combo to inspire us to speculation. (In Hawaii the constellation is called Kuhi, another evocative name; in China it was Xuánwu, the “Black Tortoise” depicted with serpentine extrusions.) Early Christian astronomers just followed Ovid and called it Belua Ponti, “the Beast of the Sea,” while the late Chaldean astronomer Berossus may have called it Thalatté, a variation on Tiamat, the Chaos Serpent (cognate with the Hebrew tahom, “the Abyss”).

C-t and Th-l, now. Manilius describes Cetus in the (1st century CE) Astronomicon: “Ocean clamors in every quarter, and the very mountains and crags quake at the creature’s onset.” A mountain walked … or stumbled. Return with me to the myth again: Perseus wields the head of Medusa (Algol) to petrify Cetus, the Abyssal Monster. A variable star — a change in the stars — turns C-t/Th-l to stone, or perhaps merely seals him up in stone. Manilius or Berossus or Ptolemy guessed (or perhaps knew) that these four variable stars were the four keys to awakening the Great Old Ones. They linked each of them with the tale of Andromeda knowing that every year the tale retells itself in heaven: Cetus is unleashed and frozen again in a night. A very special night that we call Halloween.