Betelgeuse in the birth chart: the red shoulder of Orion

Star data

sefstars catalogue, Swiss Ephemeris 2.10.03.

Betelgeuse is a red supergiant on one of Orion's shoulders. Ptolemy gave the shoulders of Orion the nature of Mars and Mercury, and tradition reads the star through that pairing as quick thinking and sharp speech. In the zodiac it stands at the very end of Gemini and will cross into Cancer in about 60 years.

Betelgeuse in the sky

Betelgeuse is a variable star: its light rises and falls, and in the winter of 2019-2020 it dimmed noticeably and drew wide attention. Ptolemy's description does not depend on brightness, so the reading does not follow these changes.

The star's size is hard to picture: put in place of the Sun, its surface would reach beyond the orbit of Jupiter. One of the newer models, published in 2020, puts its mass at 16 to 19 solar masses. Its distance is poorly known: the same study gives about 530 light-years, while NASA quotes about 725.

Observations with the Hubble telescope explained the dimming of 2019-2020. A huge mass of hot material burst from the star's surface, moved outwards, cooled and became a cloud of dust that blocked part of its light. By mid-February 2020 Betelgeuse had lost more than two-thirds of its brightness, a change visible even without a telescope.

In 2025 a NASA-led team reported the probable detection of a long-predicted companion of Betelgeuse in images from the Gemini North telescope in Hawaii. They named it Siwarha, meaning "her bracelet". The finding still needs confirmation: the companion will next reach its greatest distance from the star in November 2027, when the observation can be repeated. At the end of its life Betelgeuse will explode as a supernova, but by the same 2020 calculations not for more than a hundred thousand years, and it is too far away for the explosion to have any significant effect on the Earth.

For an astrologer the red colour is an easy reminder of the Martial part of its nature. In the same constellation lies Rigel, whose nature in Ptolemy is quite different, Jupiter and Saturn. Two bright stars of one figure with such different natures show that a constellation is not read as a single whole.

Finding it from Ukraine

Betelgeuse is a star of winter evenings, and it stands highest at midnight in the second half of December. Orion leads to it: the three belt stars sit in the middle of the figure, and the bright red-orange star to their upper left is Betelgeuse. Diagonally across, below and to the right of the belt, stands bright Rigel. With Sirius and Procyon, Betelgeuse forms the Winter Triangle. In Kyiv it rises to about 47° above the horizon, in Odesa to about 51°.

Name and history

Betelgeuse is a garbled form of an Arabic phrase meaning "the hand of al-Jauza", the old Arabic figure in this part of the sky. Over the centuries the original phrase changed shape, and the modern spelling is the result. The name records the star's place in an old picture of the sky, not its nature.

In Arabic the phrase is Yad al-Jauza: al-Sufi's tenth-century Book of the Fixed Stars gives it for this star alongside "the shoulder of al-Jauza". In European copies the start of the name was garbled, "Yad" turned into "Bed", and after that the name went through many spellings, from Riccioli's Bedalgeuze to the modern one. Allen, in his 1899 book on star names, derived it from a different word, "the armpit of al-Jauza", a reading that modern scholars regard as a mistake. He also lists other Arabic names for the star: the shoulder, the arm and the right hand of the giant. The name Betelgeuse was approved by the International Astronomical Union in 2016.

Nature by tradition

In the first book of the Tetrabiblos Ptolemy says that the stars on Orion's shoulders are like Mars and Mercury.

Mars adds drive and a readiness to compete; Mercury adds intellect and speed. Together they describe a mind that works fast and acts on what it sees: quick judgment, skill with tools and instruments, an ability to make decisions under time pressure. The rougher side of the pairing is haste and words that come out sharper than intended.

Conjunctions with planets and angles

Tradition counts a contact with a tight orb, usually around 1°. Two examples:

• Betelgeuse on the Ascendant. The Ascendant is the angle of personal manner, so the Mars and Mercury themes show in how a person comes across: direct, quick to react, frank in speech. The planets aspecting the Ascendant and its ruler soften or sharpen this.
• Betelgeuse with Mercury. Here the star adds Mars to a planet that is already Mercurial. Tradition reads the conjunction as a sharp, debating intelligence and fast speech. If natal Mercury also has hard aspects to Mars, hasty words become a stronger theme; if it is well supported, the same speed reads as mental agility.

Precession and the move into Cancer

Betelgeuse is now at the very end of Gemini and, through precession, will reach Cancer in roughly 60 years. In charts of people born after that, it will stand in early Cancer. The sign only says where the star is; its nature still comes from Ptolemy's planets.

In practice the border matters in two ways. Positions drift by about 1.4° a century, so old tables give the star in a noticeably earlier degree of Gemini, and using them shifts every contact. And because the star already sits right on the border, a planet in the first degree of Cancer can be within orb of it today. Such a contact counts: it is checked by the actual distance in degrees, not by the sign names.

In celebrity charts

Conjunctions within 1° to the planets from the Sun to Saturn and to the chart angles.

• Boris Johnson: Sun, orb 0°11′

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