M45, also known as the Pleiades throughout the USA, or the Seven Sisters in Greek mythology, or Subaru in Japan, Persian name Soraya, is an open cluster of new – astronomically speaking – stars. This group of stars can be seen with the unaided eye, which is one of the reasons it is so popular among many people, and has been referenced long ago, and also mentioned by Homer around 750 B.C., by biblical Amos around 750 B.C. and by Hesio around 700 B.C. At least 6 of the stars can be seen with the unaided eye, with the number increasing to 9 or so under clear dark skies. On March 4, 1769, Charles Messier added the Pleiades to his list of clusters and nebula published in 1771. It wasn’t until long exposure photography that we realized that the stars of the Pleiades are imbedded in a nebulous material, which are a blue color, which indicates it is a reflection nebula. The brightest of the nebula around Meope was discovered on October 19, 1859 by Ernst Wilhelm Leberecht (Wilhelm) Tempel in Venice. It wasn’t until the later 1880s that the nebulae around Alcyone, Electra, Celaeno and Taygeta were found in photographs.
The nebulae found in the cluster are most likely part of a molecular cloud that is unrelated to the Pleiades star cluster. Many people have believed that the dust in the images is leftover from the formation of the stars, but it does not appear to be associated with the stars due to having different radial velocities. It is calculated that the stars of the Pleiades age is around 100 million years old, with a future lifetime expectancy of another 250 million years. By which time the stars will have spread out onto their own orbital paths. The ESA have determined the distance to the cluster using direct parallax measurements estimating a distance of 380 light-years. Using the Hubble Space Telescope and the Mount Palomar and Mount Wilson Observatories the distance is more accurately estimated to be 440 +/- 6 light-years.
Information from the Messier Catalog
My observations were short that night as it was a bit cold. I didn’t spend more time than I had to outside at the telescope. I did take a couple minutes to soak in the view of the Pleiades. There are no signs of nebula without photography, so even in my telescope it was just bright blue stars arranged in an almost Ursa Minor formation. As a kid I always thought the Pleiades was the little dipper, as it has a shape sort of similar; I believe that may just be due to the way the stars Maia, Electra, Merope, Alcyone, and Atlas form a bowl and handle shape like the dippers.
M45/Pleiades/Seven Sisters/Subaru 12-19-14
This image is 25 light frames at 5 minutes a piece, 25 Flat Frames, 25 Flat Dark Frames, and 12 Dark Frames. Stacked in a new-to-me software, IRIS and following a tutorial by Jim Solomon’s IRIS Cookbook with some small minor touches in Photoshop.
Omni XLT 150
CG-5 Advanced Series Go-To
Orion Starshoot Autoguider
Modified Canon 350D
Baader MPCC Mark III Coma Corrector