Altair in the birth chart: the star of the flying eagle

Star data

sefstars catalogue, Swiss Ephemeris 2.10.03.

Altair is the brightest star of Aquila, the Eagle, and one corner of the Summer Triangle. Its Arabic name means "the flying one", from the old title "the flying eagle". In the tropical zodiac Altair stands at the very beginning of Aquarius, a sign it entered only in the nineteenth century. Ptolemy gave the stars of the Eagle the nature of Mars and Jupiter, the same formula he gave Regulus.

In the sky

Altair is about 17 light-years away. It is a white main-sequence star of class A7, almost twice the Sun's mass, and it spins so fast that the spin shows in its shape. A single rotation takes only about nine hours.

That spin has flattened the star. In 2007 a team led by John Monnier used the CHARA interferometer to make an image of Altair's surface: the equatorial radius is about a fifth larger than the polar one, and its rotation rate is about 90% of the rate at which its equator would start to shed material. Its poles are hotter and brighter than its equator, roughly 8,700 K against 6,900 K. The effect is called gravity darkening, and in the CHARA image it can be seen directly rather than only inferred from models.

Altair lies far from the ecliptic, about 29° to the north. A conjunction with it by longitude is therefore a projection: a planet at the same zodiac degree is a long way from the star in the sky. For stars like this some astrologers prefer parans.

Finding it from Ukraine

Altair is a star of summer and early autumn. It stands highest at midnight in mid-July, and by September it is already high in the south in the evening. The easiest way to find it is the Summer Triangle: Vega, Deneb and Altair form a large figure, and Altair is its southernmost corner. A second clue: two fainter stars, Gamma and Beta Aquilae, stand on either side of Altair, two or three degrees away, and the three line up almost in a row.

From the latitude of Kyiv Altair climbs to about 48° above the southern horizon at its highest, so it is easy to see from anywhere in the country, even from a city.

The name

The star-name historian Richard Hinckley Allen explains that Altair comes from part of the Arabic name for the constellation, al-Nasr al-Tair, "the flying eagle", and that this name was confined to the three bright stars together, Altair and its two neighbours. In contrast, Vega was "the swooping eagle", its wings half folded (see the Vega page). The word for eagle in these languages could also mean a vulture, so Latin maps sometimes call the constellation Vultur volans, "the flying vulture".

The Greek name Aetos, "eagle", in Ptolemy's Almagest is, Allen says, one of Ptolemy's few names for individual stars and was probably first given to Altair. In Latin stories the eagle served Jupiter and carried Ganymede up to the sky. In China Altair is the Cowherd from the tale of the Cowherd and the Weaver Girl, who is Vega; a bridge of magpies leads him to her. The International Astronomical Union approved Altair as the star's official name in 2016.

Nature according to Ptolemy

In the first book of the Tetrabiblos Ptolemy treats the stars of the Eagle together, in a single phrase: "those in Aquila, of Mars and Jupiter". He gives the same pair to the star on the Lion's heart, Regulus.

Mars stands for courage, speed, a readiness to take risks and to make the first move. Jupiter adds scale, confidence and the wish for something bigger. Together they describe a bold, enterprising temperament that takes on large undertakings. Read through this pair, the star suggests daring and a readiness to aim high, with haste and a tendency to overestimate one's strength as the reverse side.

After Ptolemy

Altair is not one of Agrippa's fifteen Behenian stars. Allen, who collected star lore at the end of the nineteenth century, notes that in astrology it was considered a mischief-maker.

Conjunctions with planets and angles

Altair is used by conjunction, with an orb of about 1°. It is a first-magnitude star, so tradition gives it more weight than fainter ones, though its distance from the ecliptic takes something away from that. Two typical cases:

• Altair on the MC. On the angle of career and public life, astrologers read the Mars and Jupiter tone as boldness in one's work, a wish to take on ambitious projects and to be seen.
• Altair with Mars. A star that is itself half Mars strengthens the planet: decisiveness, quick reactions, a competitive streak. Whether this shows as initiative or as impatience depends on the rest of the chart.

Precession and the change of sign

Like every star, Altair drifts slowly along the zodiac (precession), and it crossed a sign boundary quite recently: it moved from Capricorn into Aquarius in the 1870s. Most books from the nineteenth century therefore place it at the end of Capricorn, and the chart of someone born before then does have it there. In charts from the twentieth and twenty-first centuries it sits at the start of Aquarius. Its nature does not change with the sign.

In celebrity charts

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

• IShowSpeed: Sun, orb 0°11′
• Jennie: Mercury, orb 0°12′
• Barack Obama: Jupiter, orb 0°21′

Find fixed stars in your chart