Star cluster or Galaxy cluster?


Galaxy cluster. The elliptical (not round) shapes are the giveaway.
cheers,
–dustin

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Another way to tell that they are galaxies is that it isn’t very bright per area of sky compared to a star. You can see other objects behind it as well. Stars are dense, and most which aren’t too bright have a small or no halo around them, and almost all stars have diffraction spikes

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Also using “Look up in SIMBAD” works well for this cluster:
ACO 1466 – Cluster of Galaxies

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