The Pleiades star cluster is one of the most important objects in the night sky. Easily identified with the naked eye it has been part of human culture for millennia in various communities across the planet Earth. There is some evidence that it served to mark the line of nodes, later the "first point of Ares" or zero right ascension, many millennia ago. It has certainly been important to mark the seasons and to indicate when it is safe to sail the ocean blue (or the Mediterranean at least).
I have produced a few images of this star cluster but none that I was completely satisfied with. It is a fantastic target so I decided to try again with the goal of an image good enough to print. One problem I saw was that the main stars (sisters?) are quite bloated. After working with this image I have concluded that the stars are actually big and there is nothing to be done. Perhaps this is because of the dust around them, who knows? The image here is a composite of a bright image with the stars removed and then processed. This was then combined with a dim image with (mostly) smaller stars. The end result is that the stars don't overwhelm the blue nebulosity... except that the "sisters" are still bloated!
Image 1: The Pleiades, The Seven Sisters, Subaru, M45. Observed August 15/16 2024 at Lac Teeples.
I recall a conversation a few years ago at a Bar-B-Que in the Cayman Islands. I had been showing off objects in my telescope and a woman said that her favorite constellation was the Pleiades. I recall biting my tongue and saying “yes, one of the greatest of all constellations”. Of course it is a star cluster, not a constellation!
I happen to drive a Subaru Impreza and it was quite a while before I realized that the Subaru logo was a stylized image of the Pleiades, known as Subaru in Japan. According to Wikipedia: "Subaru is the direct translation from Japanese for the Pleiades star cluster M45, or the "Seven Sisters" (one of whom tradition says is invisible – hence only six stars in the Subaru logo)". Note the blue background in the Subaru logo (Image 2).
Also according to Wikipedia: "Parveen Parvin, Perveen, Pervin or Parween.(Persian: پروین) is a Persian-Kurdish given name meaning Pleiades. It is commonly used in Iran, Afghanistan, Tajikistan, Pakistan and India. It is also used as a last name." The Pleiades are mentioned three times in the Bible. A more complete account of the cultural significance is in the Wikipedia article linked below.
Image 2: Subaru logo
The Pleiades is an open star cluster very near to the Earth (400 light years away) located in the constellation Taurus. The blue nebulosity, known as NGC1432, is from reflection of light rather than emission. The cluster of young and hot stars is drifting through a cloud of dust which reflects their light. The blue colour suggests that these stars are VERY hot. The radius of the core cluster is around 8 light years, and there are a total of 1000 stars in the cluster: The sisters are merely the brightest of the group.
In 1610 Galileo published a sketch of the cluster showing 36 stars. See image 3. I see that he titles this page "Pleiades Constellation"... I'll have to have a talk with him about that.
Image 3: Sketch of the Pleaides from Sidereus Nuncius, Galileo, 1610.
Overall I'm satisfied with this image, but still a bit concerned by the bloated "sisters". I will make a print and add it to the collection. I suspect that the large "sisters" will look good in a print, just as the saturated core in my Andromeda image looks good and adds a sense of magnitude to the image.
Image of the Pleiades captured August 15 and 16, 2024 at Lac Teeples. Equipment: RASA-11, repaired CEM70 mount, ZWO ASI6200MC colour camera. Roughly four hours of 64 second subframes collected, but only 110 minutes were usable due to moonlight, whisps of cloud and other problems. No narrowband imaging was used (no emission lines of note in a reflection nebula). Two images were created, one bright one with the stars removed and one dim one. The dim one was overlaid on top to add back the stars.
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