Messier 6. NGC 6405

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Messier 6 (M6) or NGC 6405 is a mature open cluster (age: about 100 Million years old). Usually, this kind of clusters contains only massive, hot, young blue stars, but M6’s brightest star is BM Sco, an orange K-type giant. This cluster is located in the constellation Scorpius at a distance of 1,585 light years. The orbit of this cluster around the galactic center was determined in 2009 by Wu et al. Its orbit is pretty much circular (eccentricity 0.03) and lasts for 204.2 Million years. As many as 120 stars (magnitude 15.1 and above) have been identified to belong to this cluster.


Additional Information


Name(s): Messier 6. NGC 6405. Butterfly Cluster

Type: Open Cluster

RA:  17h 40m 19s

Dec: -32º 14’ 54”

Constellation: Scorpius

Size (arcmin): 25 arcmin

Magnitude: +4.2

Distance: 1,595 ly


Date: 2020-05-27 to 2020-07-24

Location:, SSO near Coonabarabran, NSW Australia

Size (arcmin): 37×37 arcmin

Telescope: 20” f/6.8 Reflector

Camera: SBIG STX16803 (4096x4096pix)

Guiding: Astrodon MonsterMOAG off-axis guider

Total exposure: 5 hours (L: 2 hours; RGB: 3 hours)

Processing: CCDStack, Photoshop CC 2020

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