Tag Archives: M45

Pleiades, M45


In astronomy, 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 celestial entity has several meanings in different cultures and traditions.

The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million years. 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 alternate 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.

Imaging telescopes or lenses: William Optics GT102 102mm f/6.9 Apo Refractor
Imaging cameras: Canon 600D astromod
Guiding telescopes or lenses: William Optics 50mm Guidescope
Guiding cameras: Orion StarShoot Autoguider
Software: Adobe Photoshop deepsky stacker
Resolution: 2601×1732
Dates: Nov. 15, 2014
Frames: 10×600″
Integration: 1.7 hours
Avg. Moon age: 22.46 days
Avg. Moon phase: 46.67%
RA center: 56.736 degrees
DEC center: 24.130 degrees
Pixel scale: 3.040 arcsec/pixel
Orientation: 94.099 degrees
Field radius: 1.319 degrees

Author:  Cadby

M45, Pleiades

In astronomy, 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 celestial entity has several meanings in different cultures and traditions.

Imaging telescopes or lenses: Orion 80ED
Imaging cameras: Canon EOS 1000D / Rebel XS
Mounts: Orion Sirius EQ-G
Guiding cameras: Orion Star Shoot Planetary Imager & Autoguider
Focal reducers: Orion 0.85x Reducer/Corrector
Software: DeepSkyStacker, PHD guiding, photoshop, Canon EOS
Dates: Oct. 7, 2011
Frames: 24×240″ ISO1600
Integration: 1.6 hours

Author: Mike Carroll
AstroPhotography of the day by SPONLI 10 Sep 2014


The nine brightest stars of the Pleiades are named for the Seven Sisters of Greek mythologySteropeMeropeElectraMaiaTaygetaCelaeno, and Alcyone, along with their parents Atlas and Pleione. As daughters of Atlas, the Hyades were sisters of the Pleiades. The English name of the cluster itself is of Greek origin (Πλειάδες), though of uncertain etymology. Suggested derivations include: from πλεῖν plein, “to sail,” making the Pleiades the “sailing ones”; from πλέος pleos, “full, many”; or from πελειάδες peleiades, “flock of doves.” 

Pleiades bright stars
Name Pronunciation (IPA & respelling) Designation Apparent magnitude Stellar classification
Alcyone /ælˈsaɪ.əniː/ al-sy-ə-nee Eta (25) Tauri 2.86 B7IIIe
Atlas /ˈætləs/ at-ləs 27 Tauri 3.62 B8III
Electra /ɨˈlɛktʃrə/ i-lek-trə 17 Tauri 3.70 B6IIIe
Maia /ˈmeɪə/, /ˈmaɪə/ maymy 20 Tauri 3.86 B7III
Merope /ˈmɛrəpiː/ merr-ə-pee 23 Tauri 4.17 B6IVev
Taygeta /teɪˈɪdʒɨtə/ tay-ij-i-tə 19 Tauri 4.29 B6V
Pleione /ˈplaɪ.əniː/ ply-ə-nee 28 (BU) Tauri 5.09 (var.) B8IVpe
Celaeno /sɨˈliːnoʊ/ sə-lee-noh 16 Tauri 5.44 B7IV
Sterope, Asterope /ˈstɛrɵpiː/, /əˈstɛrɵpiː/ (ə)-sterr-ə-pee 21 and 22 Tauri 5.64;6.41 B8Ve/B9V
18 Tauri 5.65 B8V

Imaging telescopes or lenses: TMB 92SS
Imaging cameras: SBIG ST-8300C, SBIG ST-8300M
Mounts: Sky-Watcher HEQ5
Guiding telescopes or lenses: TMB 92SS
Guiding cameras: QHYCCD QHY5
Focal reducers: Teleskop-Service TS 2.5″ flattener
Software: Maxim DL, photoshop
Filters: Baader Planetarium UV/IR Cut Filter, Hutech IDAS LPS-P2
Accessories: Teleskop-Service OAG 9mm
Dates: Sept. 17, 2012, Sept. 24, 2012
Hutech IDAS LPS-P2: 40×600″ bin 1×1
Baader Planetarium UV/IR Cut Filter: 25×600″ bin 1×1
Integration: 10.8 hours

Author: Jacek Bobowik
AstroPhotography of the day by SPONLI 30 June 2014

M45: Pleiades in Taurus

beb3da4c3bb6b10a808dfc4376f99b96.1824x0_q100_watermark_watermark_opacity-10_watermark_position-6_watermark_text-Copyright Giulio Ercolani
Seven Sisters (Messier object 45 or M45), is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus.  The most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city.

Under ideal observing conditions, some hint of nebulosity may be seen around the cluster, and this shows up in long-exposure photographs. It is areflection nebula, caused by dust reflecting the blue light of the hot, young stars. It was formerly thought that the dust was left over from the formation of the cluster, but at the age of about 100 million years generally accepted for the cluster, almost all the dust originally present would have been dispersed by radiation pressure. Instead, it seems that the cluster is simply passing through a particularly dusty region of the interstellar medium. Studies show that the dust responsible for the nebulosity is not uniformly distributed, but is concentrated mainly in two layers along the line of sight to the cluster. These layers may have been formed by deceleration due to radiation pressure as the dust has moved towards the stars.

Imaging telescopes or lenses: Takahashi FSQ Fluorite
Imaging cameras: SBIG STL-11000M
Mounts: Paramount GT-1100S
Dates: Oct. 2, 2013
Locations: Mayhill
4×300″ bin 1×1
RGB filters: 3×300″ bin 1×1
Integration: 0.6 hours

Autor: Giulio Ercolani

AstroPhotography of the day by SPONLI

28 January 2014

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