Look again
A constellationis more than its illustration
Learn the bright stars first. Trace the line that joins them. Then listen for the stories people have hung on that line for ten thousand years.
Marks on each heading:Attributed A named tradition or text says this. It is not proof that anything will happen.Calculated An observation from astronomy or arithmetic, with its conventions stated.Editorial Our own wording. It is not a quotation of any source.
01Two different ideasCalculated
The astronomical constellation is a region of sky with agreed boundaries and a pattern of stars. The astrological sign is a thirty-degree division of the zodiac belt. Western astrology measures it from the equinox (tropical); Jyotisha measures it against the fixed stars (sidereal). They share names, and they are not the same thing.
Lines joining stars are conventions. There is no single official stick figure for any constellation, and the charts here follow one published edge list for each.
02How to read a star chartCalculated
Each chart on this page is drawn from catalogue positions of real stars. North is up and east is to the left, as on a printed sky map, because you are looking up at the sky and not down at the ground. The picture is flattened using a gnomonic projection, which keeps straight lines on the sky straight on the page.
The size of a dot shows the star’s brightness. Astronomers measure it as magnitude, an ancient scale where a smaller number is brighter. The brightest stars are around 0 or 1. The faintest you can see from a dark site are near 6. A difference of five magnitudes is exactly a hundredfold in brightness. Under a city sky, expect to see only stars brighter than about 3, which is why Cancer and Pisces can seem to vanish.
The dotted lines are one convention for joining the stars into a pattern. Other maps join them differently, and cultures have drawn entirely different figures from the same stars.
03Why the signs are not the constellationsCalculated
The twelve signs each take thirty degrees, an equal share. The constellations do not. Along the Sun’s path, Virgo is more than six times as long as Scorpius, and the Sun also crosses a thirteenth constellation, Ophiuchus.
This is one reason astronomers object to using the constellations as a calendar. Astrologers answer that the signs were never meant to be constellations. They are a coordinate system with traditional names, the way lines of longitude carry the name of a city.
04The twelve figuresCalculated
Open any chart for the full article on its sign. “High at 9 pm” gives the month when the constellation crosses the southern sky around nine in the evening, for observers in the northern mid-latitudes. Scorpius and Sagittarius stay low from far north and are better seen from the south.
AriesMeṣa
Between the Pleiades and the bright star Mirach in Andromeda; Hamal is the only star here brighter than magnitude 2.5.
TaurusVṛṣabha
Follow Orion’s belt up and to the right to the orange eye, Aldebaran; the Pleiades sit just beyond.
GeminiMithuna
Find the two bright heads, Castor and Pollux, side by side; the bodies run toward Orion.
CancerKarka
A faint patch between Gemini and Leo; look for the soft glow of the Beehive Cluster on a dark night.
LeoSimha
Look for the Sickle, a backward question mark, ending at the bright star Regulus.
VirgoKanyā
Follow the arc of the Big Dipper’s handle to Arcturus, then continue to Spica.
LibraTulā
A dim pair of claws east of Spica and west of the red star Antares.
ScorpioVṛścika
A red star, Antares, marks the heart; a long hook of stars curls to the sting.
SagittariusDhanus
The Teapot, with its spout pointing toward Scorpius, sits in front of the thickest part of the Milky Way.
CapricornMakara
A faint triangle south-east of Altair; Deneb Algedi marks the tail.
AquariusKumbha
A faint field south of the Great Square of Pegasus; the Y-shaped Water Jar is the easiest part to find.
PiscesMīna
Two faint fishes joined by a cord that begins just south of the Great Square of Pegasus.
05Where the data comes fromCalculated
Star positions and magnitudes are drawn from the Hipparcos-derived catalogue as published in the d3-celestial data set. The connecting lines follow its edge list. This is a projection for orientation, and it is not an observing-grade chart. Names are the common proper names for the stars, and several faint stars are known only by their Greek-letter designations and are left unlabelled.