The Pleiades, Messier 45, are an open star cluster in Taurus, roughly 440 light-years away. An open cluster is a group of stars associated through their birth and gravity, rather than a chance outline drawn between unrelated stars. The bright points visible to the unaided eye are only its most conspicuous members. NASA’s Hubble Messier catalogue gives the cluster an integrated visual magnitude of 1.6 and describes more than a thousand members. Integrated magnitude combines their light; it is not the magnitude of every star or a promise that faint nebulosity will be easy to see. Source: NASA, Messier 45, https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/hubble-messier-catalog/messier-45/.
This grouping has been observed since antiquity and has no single known discoverer. Its catalogue designation does not mean that Messier discovered it. Galileo’s telescopic observations revealed stars beyond the familiar unaided-eye pattern. What looks like a small handful becomes a much richer field when an instrument collects more light. The historical Seven Sisters name describes a cultural pattern; it is not an astronomical count of the cluster’s population. Source: NASA’s Hubble Messier catalogue, above.
The stars are young on the scale of stellar evolution, with an age of roughly 100 million years. Their surrounding dust was once interpreted as leftover material from their formation. NASA’s WISE account explains why that is unlikely: radiation and stellar winds should have dispersed the original material by this age. The cluster is probably passing through interstellar dust. In visible photographs, some of that dust scatters starlight toward us, making reflection nebulosity. The dust does not have to generate its own visible light to appear luminous in the picture. Source: NASA/JPL-Caltech, Seven Sisters Get WISE, https://science.nasa.gov/photojournal/seven-sisters-get-wise/.
Infrared pictures tell a complementary story. WISE detects emission from warm dust as well as stellar light. Its published colours encode different infrared wavelengths; they are not the colours an observer would see through an eyepiece. A blue visible reflection cloud and red-coded infrared dust can represent different observations of the same region. Before comparing a photograph with the visual view, check what wavelengths and display colours the image uses. Source: NASA/JPL-Caltech’s WISE account, above.
The familiar cluster is also part of a much more extended proposed family. In November 2025, NASA reported a study identifying more than 3,000 associated stars across about 1,900 light-years, called the Greater Pleiades Complex. Researchers combined Galactic motions, stellar rotation and chemical abundances. Rotation provided an age clue because stars generally slow as they age; similar chemistry offered another test of shared origins. This is evidence for a dispersed stellar population, not a claim that a backyard view suddenly contains three times as many bright Sisters. The interpretation can be refined by later observations. Source: NASA, NASA’s TESS Spacecraft Triples Size of Pleiades Star Cluster, https://science.nasa.gov/missions/tess/nasas-tess-spacecraft-triples-size-of-pleiades-star-cluster/.
For finding the cluster, begin with Orion’s Belt, follow its line toward orange Aldebaran and the Hyades V, then continue in the same general direction to the compact Pleiades grouping. Match the chart’s whole arrangement. A wide binocular field preserves the cluster’s context; high magnification can crop the pattern and make recognition harder. The stars are much easier visual targets than their faint surrounding dust. A photographic blue veil is not a reliable expectation for an ordinary glance through binoculars.
Let the weekly almanac supply the changing conditions: darkness, Moon interference, altitude and any nearby planet. The stored cluster story remains useful when those conditions change. A planet crossing this field is a visitor in projection; it does not belong to the cluster. Finding instructions here are original Star Almanack wording based on the accepted guide-star route.
