"Pleiades Cluster, also known as the Seven Sisters, is an open star cluster located approximately 390 to 456 light years from Earth in the constellation of Taurus."
"The nine brightest stars of the Pleiades are named for the Seven Sisters of Greek mythology: Sterope, Merope, Electra, Maia, Taygete, Celaeno, and Alcyone, along with their parents Atlas and Pleione."
"As one of the closest of star clusters to our solar system, M 45 is dominated by hot blue stars that have only formed within the last 100 million years. Alongside Maia is a reflection nebula discovered by Tempel faint nebula which accompanies Merope was discovered by master observer E.E. Barnard."
“Unusually massive amounts of dust, as seen at the Pleiades and Aries stars, cannot be primordial but rather must be the second-generation debris generated by collisions of large objects,” said Song, “”Collisions between comets or asteroids wouldn’t produce anywhere near the amount of dust we are seeing.”  https://www.universetoday.com/34994/messier-45-pleiades/

“The scattering geometry analysis is complicated by the blending of light from many stars and the likely presence of more than one scattering layer. Despite these complications, we conclude that most of the scattered light comes from dust in front of the stars in at least two scattering layers, one far in front and extensive, the other nearer the stars and confined to areas of heavy nebulosity"
"...The association of nebulosity peripheral to the main condensation around the brightest stars is not clear. Models with standard grain properties cannot account for the faintness of the scattered UV light relative to the optical."http://iopscience.iop.org/article/10.1086/374590/meta

"As a matter of perspective, the faintest stars (of the bright stars noted) in M 45, are still 40 times brighter than our own sun would appear at a similar distance, and the brightest Pleiad, Alcyone, is 1000 times more luminous! Stars like our sun, of which there are a few in the cluster, appear as faint flecks of light in the AAO photograph at the top of this page, and are well below the sensitivity of the human eye."  https://www.naic.edu/~gibson/pleiades/

Nebulosity in the Pleiades
"....the nebula and cluster have different radial velocities – crossing each other with a relative velocity of 11 km/s. Though not visible to the eye, long photographic exposures show this reflection nebula enmeshing the whole crowd. The nebula is particularly bright around Merope".https://www.daviddarling.info/encyclopedia/P/Pleiades.html

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Since I was a child I called them 'The question mark'. Finally I process this old data and I was very curious what we catch of it.

The image comes from two session done in our backyard where we could run for the first time successfully PH2 (24 and 27 Dic 2019) and from a session done in the central Alps in a point panoramic view at 845 msl close to Cesena (August 2020).

I had to use the sessions in two ways, the first session became the base stars because of the way that was done and the second and third as the base of the dust/reflection nebula.  The third session Maurizio had problem with the guide cable (broke) and is the reason for the subs was done with only 20 sec exposure because was unguided.

In the process I did a normal bilinear stack as the stars obtained of the first session was good enough, the stars in and around the cluster present nice colors.  The reflection part was more delicate as also notice the brownish dust around in some parts of that area that I liked a lot, as confer some unusual deep. I also worked the stack done in Siril with the processing tools of that program in linear mode (Photometric color calibration, Background extration,) and after Asinh Transformation manually as sometime the Histogram Transformation  default is excesive. The other stack from DSS I worked as usual all in Ps and then blend both. I did several passes in camera raw and one light denoise.  The reflection part was worked starless...

Doing the starless part was fun as the two programs give different result. StarXterminator almost empty all, the stars and the big spikes of the Newton while StarNet V2 empty all the stars, the bright stars centre but not the big spikes. Also let in the big stars a colorish centre that I have to work around for neutralize that area in each big star. So I worked apart each image and blend it together and then after incorporate the base image stars session one finally.

Maurizio and I agree we need to do in the future a proper project sessions on the Pleiades, because they have so much to offer visually, the faint lanes, all the extensive dust around that area, is really spectacular and deserve be done with more care.

Thank for visit us and see our work.

Process June 2022

https://twitter.com/AstroOtus/status/1537922802468069379