The Pleiades or the Seven Sisters form a beautiful star cluster near the constellation Taurus. This is one of the closest star clusters to Earth and perhaps the most beautiful to the naked eye. Over the millennia, it has inspired folklore around the world and is now being studied as a recent birthplace of new stars.
Steps
Method 1 of 2: From the Northern Hemisphere
Step 1. Look for the Pleiades in the fall and winter
In the northern hemisphere, the Pleiades cluster becomes visible to evening watchers in October and disappears in April. November is the best time to search for the Pleiades as they are visible from dusk to dawn and reach their highest point in the sky.
- In early October, the Pleiades become visible a couple of hours after sunset. In February, the Pleiades are already high in the sky by the time the sun goes down. (The exact time depends on the latitude).
- The Pleiades are also visible in late summer and early fall but only in the middle of the night.
Step 2. Look at the sky to the south
The Pleiades emerge in the southeast after sunset and drift west at night. At their highest point in November, they disappear to the northwest before dawn. In late winter and early spring, they are only visible for a few hours, moving from east to west across the southern part of the sky.
Step 3. Find Orion
Orion the Hunter is one of the most famous and distinctive constellations in the sky. On a winter night at mid-north latitude, it is almost due south, around the midpoint between the horizon and the sky directly overhead. Locate him by his belt, a straight line of three bright stars next to each other. The red star near there, Betelgeuse, forms his left shoulder (from your perspective), while the blue giant Rigel on the other side of the belt is his right leg.
Step 4. Follow the belt line to Aldebaran
Use the Orion belt as an arrow pointing to your next landmark, moving left to right across the sky (most of the time in most places, it will point northwest). The next bright star you see in this direction is another reddish-orange star: Aldebaran. This word means "follower" in Arabic and is likely so named because it haunts the Pleiades every night.
- Aldebaran is not perfectly aligned with the belt. Don't try to find it with binoculars or you could lose sight of it.
- Aldebaran falls below the horizon in approximately March or earlier in extreme northern latitudes. If Aldebaran is not visible, try to follow Orion's belt to the Pleiades.
Step 5. Keep going to find the Pleiades
Keep moving your eyes in the same direction (usually northwest) from the Orion belt to Aldebaran and beyond. Quite close to Aldebaran you should see a narrow cluster of blue stars. These are the Pleiades, also called the Seven Sisters or M45.
- Most people can only see six stars with the naked eye or even just a fuzzy group if light pollution interferes. On a clear night and with sharp, dark-adapted eyes, you could see more than seven.
- The Seven Sisters are grouped very close to each other. The distance from one end of the cluster to the other is just two-thirds of the width of Orion's belt. This is much less than the length of the Dipper or Ursa Minor, star patterns some novice observers mistake for the Pleiades.
Step 6. Use Taurus as your guide next time
The red star Aldebaran described above is also the eye of the constellation Taurus, the Bull. The nearby Hyades star cluster forms the bull's chin. If you become familiar with this constellation, you can find it as a starting point and look for the Pleiades nearby.
Taurus can be difficult to see with a bright moon, especially near an urban area
Method 2 of 2: From the Southern Hemisphere
Step 1. Look for the Pleiades in spring and summer
The Pleiades are visible from around October to April during the southern hemisphere spring and summer months.
Step 2. Look at the sky to the north
In late November, the Pleiades rise to the northeast around dusk and drift west until dawn. As the seasons progress, the Pleiades rise higher and higher in the sky and are seen for less time.
Step 3. Look for a line of bright stars
In the southern hemisphere, Orion is upside down, so some observers call this constellation "the frying pan," with the sword of Orion being the handle that points upward. The edge of the pan (or Orion's belt) is a trio of bright stars in a straight line. This distinctive shape is a starting point for locating many constellations.
This line contains the luminous red star Betelgeuse on one side and the luminous blue star Rigel on the other
Step 4. Follow the line in the sky to the left to Aldebaran
Use the line as an arrow pointing to the left across the sky. The next bright star in this direction is Aldebaran, a bright red supergiant star. This is the eye of the constellation Taurus the Bull. If the sky is clear and the moon is dim, you will be able to see the bull's chin next to Aldebaran, formed by the Hyades star cluster.
Step 5. Continue to the Pleiades
Continue following the same line from Orion's belt and you will come across a rather faint blue star cluster. These are the Pleiades, also called the Seven Sisters (although most people can only see six or fewer and telescopes can see more). The Pleiades are an "asterism", a pattern of stars much smaller than a constellation. If you lift your thumb with your arm fully extended, the cluster will only be about twice the width of your nail.
Advice
- Use binoculars instead of a telescope. The Pleiades cover a fairly large area and binoculars have a wider field of view than a telescope.
- When the Pleiades disappear, they still rise above the horizon but too close to the dawn sun to be visible. Later, approximately in May or June, they can be seen near dawn (with difficulty and clear weather). The first "heliacal sunrise" (apparition near the sun) of the year is associated with the spring festivals in some places.