Aries

What is Aries?

Constellations· Autumn evenings (N) · three stars below Triangulum. The ram of the Golden Fleece — just three stars in a short bent line, yet the first sign of the zodiac because the vernal equinox lay here two thousand years ago. Precession has since moved the equinox into Pisces.

Where Aries is in your sky right now: https://nowsky.org/solar/sky?sel=con:Aries — location and time set automatically, no login.

Stars of the figure

The 1 brightest of the 3 stars used in the figure (2 lines). Lower magnitude means brighter.

Constellation basics

Figures are representative approximations. Source: compiled from NASA and IAU public data.

Frequently asked

When can I see Aries?

autumn evenings, November–December.

How do I find Aries?

the bent line of three stars between the Great Square and the Pleiades.

What is the brightest star in Aries?

Hamal, magnitude 2.

Where is Aries in the sky right now?

Open the sky view for your location and time and it shows the position in the sky right now.

Aries in the nautical almanac — still the name of the reference point

The vernal equinox left Aries two thousand years ago, but the name stayed. The reference point from which star positions are measured in navigation and astronomy is still called the First Point of Aries, and its symbol ♈ is the ram's horns. The nautical almanac lists the point's hour angle (GHA Aries) for every day, and a star's coordinate (SHA) is added to it to fix a position. Anyone finding a ship's position by the stars still reckons from Aries today.

The equinox actually lies in Pisces now and moves into Aquarius around 2600. The name is kept because the drift of the reference point is handled by correcting for precession, whereas renaming it would set old and new tables at odds. Aries is small in stars, but as the origin of the coordinate system it is the name against which the positions of stars across the whole sky are written.

The constellation in depth

Aries is the golden-fleeced ram that carried Phrixus and Helle through the air to Colchis. Its fleece became the Golden Fleece that Jason and the Argonauts later sailed to recover. The Babylonians called these stars the "Hired Man"; the ram took shape when the constellation passed into Greek hands. Its three brightest stars sit close together, so the whole figure fits within one comfortable glance in the autumn sky.

In the era of Hipparchus, around 130 BC, the Sun stood in Aries at the spring equinox. Astrology still labels the equinox "0° Aries", although precession has carried the real equinox point into Pisces. Mesarthim, the third star, splits in a small telescope into two nearly equal white stars — a favourite double. The star Hamal, an orange giant 66 light-years away, was one of the stars Greek astronomers used to fix the position of the equinox.

On autumn evenings look east between the Great Square of Pegasus and the Pleiades: Hamal and Sheratan form a short, slightly bent line. With few bright stars, city skies may show only Hamal. In the Sky view an early December evening puts the ram high in the south. Once you have found the ram, the bright Pleiades and the V of Taurus lie just to its east, a handy stepping stone through the autumn sky.

Related

Figures are representative approximations. Simulated positions use J2000 mean elements.