Tuesday, December 27, 2016
A FAINT SPIRAL GALAXY IN PLEIADES Taken by Miguel Claro on November 6, 2016 @ Cumeada Observatory in Dark Sky® Alqueva, Portugal
The Pleiades, or Seven Sisters (Messier 45 or M45), is an open star cluster containing middle-aged, hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. The cluster contains 1,000 stars, of which more than a dozen can be seen with the unaided eye. The celestial entity has several meanings in different cultures and traditions.
The blue nebulosity that surrounds the cluster is a reflection nebula. The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million years, and are located 391 light-years away according to measurements made by the Hipparcos satellite. Dust that forms a faint reflection nebulosity around the brightest stars was thought at first to be left over from the formation of the cluster (hence the alternative name Maia Nebula after the star Maia), but is now known to be an unrelated dust cloud in the interstellar medium, through which the stars are currently passing. Computer simulations have shown that the Pleiades was probably formed from a compact configuration that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood.
In the same field of view and less obvious than the brightest hot stars from Pleiades, near the star Electra, can be seen a very faint spiral galaxy UGC 2838 (PGC13696) with a magnitude of 17.8, is beyond the limit of our human capacity to distinguish faint objects and is in the limit detection of many small optical
instruments. The named members of the
Pleiades and their magnitudes are: Pleione – 5.2 | Atlas – 3.8 | Alcyone – 3.0 | Merope – 4.3 | Electra – 3.8 | Celaeno – 5.4 | Taygeta – 4.4 | Maia – 4.0 | Sterope – 5.9
Technical details | Detalhes Técnicos
Taka FSQ-106ED + Extender-Q 1.6x – EM200 auto-guided | Nikon D810A | ISO2500 – Exp. 300 seconds x 15 lights + ISO3200 – Exp. 210 seconds x 10 lights + ISO2500 – Exp. 270 seconds x 13 lights | Total integration of 38 Lights: 2h48 minutes. Processing on PixInsight 1.8 and CS6. Cumeada Observatory from Dark Sky® Alqueva Reserve, Reguengos de Monsaraz.