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M73 is one of the three “fake”, non-nebulous, Messier objects (together with M40, double star, and M24, star patch). It contains four stars distributed as a triangle with a fourth star off-center (Y-shape). The stars do not form a sparse star cluster as they are not physically related. They simply are in the same line of sight. This as determined about a decade ago with high resolution spectra.
Additional Information
Object
Name(s): M73, NGC 6994
Type: Asterism
RA: 20h 58m 54s
Dec: -12º 37’ 59.8”
Constellation: Aquarius
Size (arcmin): 9
Magnitude: 8.9
Distance: 2,000 ly
Image
Date: 2013-08-11
Location: Corbera de Llobregat, Barcelona, Catalonia
Size (arcmin): 21×15
Telescope: Celestron 11” HD f/10
Camera: FLI ML6303 (3072x2048pix)
Guiding: Orion SSAG/Nikkor 500mm f/8
Total exposure: 40 min (L: 10min; RGB: 30min)
Processing: PixInsight