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M29 is a moderately sized open cluster with more than 30 stars. The five brightest stars in this cluster are all B0 giants (magnitudes between 8.6 and 9.2).
The light that arrives to us from this cluster is strongly filtered by interstellar matter, polarizing it and dimming the whole cluster. It would appear about 2.5-3 magnitudes brighter, should this filtering not occur.
Additional Information
Object
Name(s): M29, NGC 6913
Type: Open Cluster
RA: 20h 23m 57s
Dec: +38º 30’ 01.4”
Constellation: Cygnus
Size (arcmin): 10
Magnitude: +6.6
Distance: 3,700 ly
Image
Date: 2012-09-24
Location: Corbera de Llobregat, Barcelona, Catalonia
Size (arcmin): 18×12
Telescope: Celestron 11” HD f/10
Camera: FLI ML6303 (3072x2048pix)
Guiding: Orion SSAG/Nikkor 500mm f/8
Total exposure: 40min (L: 10min; RGB: 30min)
Processing: PixInsight