Star Clusters

Pleiades

12 July, 2026

Pleiades

About this image

The Pleiades, also known as the Seven Sisters and cataloged as Messier 45 (M45), is a prominent star cluster mentioned in the Old Testament of the Bible, appearing in Amos 5:8, Job 9:9, and Job 38:31. The cluster is dominated by hot, blue, luminous stars that formed within the last 100 million years.

The reflection nebulae surrounding the brightest stars were once believed to be remnants of their formation but are now thought to be an unrelated dust cloud in the interstellar medium through which the stars are currently passing. This dust cloud is estimated to be moving at approximately 18 km/s relative to the cluster.

Annotated image

Annotated image for Pleiades
Annotated version showing the main objects in the field.

Image details

Object type cluster associated with nebulosity
Catalogue M45, M 45 – CR 42 – MEL 22
Constellation Taurus (Tau)
Observed 2025 Jan 30 – 20:00 UTC
Location Portsmouth, UK
Moon New Moon – 3% illuminated – age 1.6 days
WordPress categories Star Clusters

Equipment

Telescope William Optics RedCat 51
Camera ZWO ASI2600MC Pro
Mount AZ/GTI
Filter Optolong L-eNhance
Focal length 250mm
F-ratio f/4.9
Pixel scale 3.1 arcsec/pixel

Acquisition

Exposure 49 x 120s
Gain 100
Guiding RMS >1.5

Processing notes

Processed in GraXpert for background extraction and denoising, then in Siril for photometric colour calibration, green noise removal, histogram stretching, and saturation adjustments.

Posted from CityAstroLog.