Messier 45 (M45) – The Pleiades

Also called the Seven Sisters or Subaru, among other things, the Pleiades is a large open star cluster only 445 light years away and containing more than 1,000 stars. The cluster is about 100 million years old. Humanity’s history with the Pleiades is ancient, going all the way back to Homer in 750 B.C. in the Iliad. Six to nine members are visible to the naked eye, depending on conditions.

The stars of the Pleiades are surrounded by nebulous material that scatters and reflects blue light—reflection nebulas. This nebulosity, however, it not leftover material from the formation of the stars in the Pleiades. Rather, it is part of the larger Taurus Molecular Cloud and just happens to be moving through the area. You can see much more of this molecular material as your eye moves away from the Pleiades. It starts to take on a more brown or gray hue. In the background, the red material is ionized hydrogen gas that is also part of the Taurus Molecular Cloud.

The most prominent stars in the cluster from our vantage include (going clockwise from the top) Electra (17 Tau), the topmost bright star in the image, Merope (23 Tau) on the right, Alcyone (25 eta Tau) at the bottom, and Maia (20 Tau) on the left. The nebulous material around these stars is particularly bright, causing Sydney van den Bergh to add them to his catalogue of reflection nebulas published in 1966 (the vdB Catalogue). A couple of them are also recorded in the NGC Catalogue.

Clockwise: vdB 20, the Electra Nebula; vdb 22 & NGC 1435, the Merope Nebula; vdB 23; and vdB 21 & NGC 1432, the Maia Nebula.

If I were an actual scientist, I could write a 1,000-page treatise on the Pleiades. There’s so much to learn about it. But I’m just an amateur trying to produce the best deep-sky images I possibly can and learn a bit along the way.

Nevertheless, there’s one obscure thing I think is worth mentioning. In 1890, American astronomer E.E. Barnard discovered a bright blob just next to the star Merope when visually observing it through the Lick Observatory’s 36-inch telescope. Scientists think this blob was created as the Merope Nebula approached the star Merope and radiation pressure from the star caused material to congeal and elongate. It’s now catalogued as IC 349 and is commonly called Barnard’s Merope Nebula.

I was very grateful to make the short list for the 2025 Astronomy Photographer of the Year contest and have this image exhibited for a year at the National Maritime Museum in Greenwich, U.K., which is located next to the storied Royal Observatory in London.