Astrology in Harry Potter: the stars behind the names
The Black family is named after the night sky, and the books are sharper about divination than they get credit for.
5 min read · Published 16 August 2026
The short answer
The Black family are named almost entirely after stars and constellations: Sirius is the brightest star in the sky and sits in Canis Major, the great dog, which matches his Animagus form; Regulus is the brightest star in Leo and means 'little king'; Bellatrix is a bright star in Orion whose name means 'female warrior'; Draco, Andromeda and Cygnus are constellations. The books also take a genuinely sceptical position on Divination — Hogwarts teaches it, most of the sympathetic characters think it is nonsense, and the two real prophecies arrive from someone who is not performing.
The Black family sky
The naming is systematic rather than decorative. A pure-blood family obsessed with lineage naming its children after fixed stars is a joke about permanence, and it runs deep enough to be worth reading as one.
| Name | What it is in the sky | The fit |
|---|---|---|
| Sirius | The brightest star in the night sky, in Canis Major, the Great Dog | His Animagus form is a large black dog. Sirius is called the Dog Star. |
| Regulus | The brightest star in Leo; the name means 'little king' | The younger brother, who dies doing something quietly kingly. |
| Bellatrix | A bright star in Orion; the name means 'female warrior' | Voldemort's most committed fighter. |
| Draco | A constellation winding around the north celestial pole; the dragon | A Slytherin heir, in a house whose sigil is a serpent. |
| Andromeda | A constellation, and the galaxy within it; a princess in Greek myth | The sister who leaves the family — chained to a rock in the myth, rescued out of it. |
| Cygnus | The swan, a northern constellation containing Deneb | A recurring Black family name across generations. |
| Arcturus | The brightest star in Boötes, fourth brightest in the sky | Another recurring family name. |
| Alphard | The brightest star in Hydra; the name means 'the solitary one' | The uncle who was disowned — struck off the family tapestry, alone. |
Alphard is the one that rewards attention. Its name means the solitary one, and the character it belongs to is the relative blasted off the family tree for helping Sirius. That is not a coincidence anyone could arrive at accidentally.
Several of these are in AsterNym's star catalogue as real objects with real coordinates — Sirius, Regulus, Bellatrix and Deneb are all bright enough to be well-documented naked-eye stars.
Why so many of those names are Arabic
Aldebaran, Altair, Deneb, Alphard, Rigel, Betelgeuse — a striking proportion of bright-star names in any European catalogue come from Arabic, and the Harry Potter names inherit that.
The reason is historical: astronomers in the Islamic world did much of the careful cataloguing during the ninth and tenth centuries, and those names passed into Latin and then into English. Alphard is from *al-fard*, the solitary one. Deneb is from *dhanab*, tail — it sits in the tail of the swan. That history is covered properly in astrology in Islam.
What the books actually say about Divination
This is the part usually missed, and it is sharper than the branding suggests.
Divination is taught at Hogwarts and is treated by most of the sympathetic characters as rubbish. Hermione walks out of the class. McGonagall is openly dismissive. The teacher spends years predicting Harry's death, incorrectly, every term. The students pass by inventing tragic-sounding predictions the night before, which works.
And yet two genuine prophecies occur — both from the same person, both delivered in a trance she has no memory of afterwards, and neither during a lesson. The structure is deliberate: the performance of divination is consistently mocked, and the real thing arrives unbidden from someone who is not trying.
Whatever you think of astrology, that is a well-made distinction. It separates the ritual from the claim, which is roughly the distinction this whole journal keeps insisting on.
The centaurs read the sky differently
The centaurs are the books' actual astrologers, and their method is nothing like a birth chart. They watch planetary movement over long periods and speak in terms of decades and eras rather than individuals — Mars being bright tonight means war is coming, not that you will have an argument.
They are also contemptuous of human divination, and specifically of reading the sky for personal fortune, which they regard as a trivial misuse of something vast. When Firenze takes over the Divination class he tells students almost nothing useful about their own lives, and that is the point of the character.
It maps onto a real distinction. Mundane astrology — reading the sky for nations, eras and collective events — is a genuine branch, and it is much older than the personal birth chart, which became the dominant form relatively late.
Centaurs are themselves a constellation, Centaurus, which contains Alpha Centauri, the closest star system to the Sun.
Other sky names in the books
- Luna Lovegood — luna is the Moon in Latin, and 'lunatic' comes from the same root, which is exactly the joke about how she is treated.
- Remus Lupin — not astronomical, but lupine and tied to the Moon's cycle through what he is.
- Merope Gaunt — one of the Pleiades. In the myth Merope is the sister who married a mortal and whose star is the faintest of the cluster; Voldemort's mother married a Muggle.
- Orion Black — the hunter, one of the most recognisable constellations, and Bellatrix's own star sits in it.
The Merope one is the deepest cut in the book. A star that dimmed because she married a mortal, given to the character whose marriage to a Muggle destroyed her.
Common questions
- Which Harry Potter characters are named after stars?
- Sirius (the brightest star in the night sky, in Canis Major), Regulus (the brightest star in Leo), Bellatrix (a bright star in Orion), Alphard (in Hydra), Arcturus (in Boötes), plus constellation names including Draco, Andromeda, Cygnus and Orion. Almost all belong to the Black family.
- Why is Sirius Black named Sirius?
- Sirius is the brightest star in the night sky and sits in the constellation Canis Major, the Great Dog — it is commonly called the Dog Star. His Animagus form is a large black dog.
- Does Harry Potter take divination seriously?
- Largely not. Divination is taught but treated dismissively by most sympathetic characters, and the Divination teacher's predictions are consistently wrong. The two real prophecies come in trances she does not remember, outside of lessons — separating the performance from the claim.
- What do the centaurs believe about astrology?
- They read planetary movement for long eras and collective events rather than individual fortunes, and they are contemptuous of humans using the sky for personal prediction. This mirrors mundane astrology, a real branch concerned with nations and periods rather than birth charts.