Pleiades Star Cluster (M 45)

Often called the  “Seven Sisters”, the beautiful star cluster Pleiades is one of the most recognisable objects in the night sky, located in the constellation Taurus. Although the brightest seven stars are very well visible to the naked eye, the cluster contains over a thousand confirmed members. These stars formed together roughly 100 million years ago, making the cluster extremely young in astronomical terms. The entire system lies about 130 pc (440 light-years) from Earth and spans ~5 pc across, drifting together through space as a loose open cluster.

The most prominent stars in the Pleiades are hot blue B-type main-sequence stars that are far more luminous than the Sun. Their intense light illuminates the delicate blue nebulosity surrounding the cluster. For many years this glowing gas was thought to be the leftover material from the cloud that originally formed the stars. Modern studies, however, indicate that the cluster is currently passing through a region of interstellar dust, and the stars are simply lighting up this material as they move through it.

The faint blue glow seen in long-exposure images is consists of a reflection rather than an emission nebula. Instead of glowing from ionisation, the microscopic dust grains scatter and reflect the light of the hot stars.  The picture was taken using red, green, and blue broadband filters producing natural colours similar to our eyes .

This image was captured from Oberes Ried in the Lötschental valley (Wallis, Switzerland) using a Takahashi TOA-150 refractor telescope with an aperture of 150mm and a focal length of 1.1m. The observation site and surrounding village are now completely burried by the Blatten glacier collapse and massive landslide from spring 2025.

Aurel Schneider 2023