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First mentioned by Ptolemy over 2 thousand years ago, it has a diameter of about 20 light years. Professional telescopic studies find that nearly 100% of the stars in M7 are binary stars, an inordinately high frequency of binaries compared to the Galactic field (where > 50% of main-sequence stars are binaries). Professional telescopic studies have counted about a hundred stars belonging to this cluster. Telescopically, M7 resembles a cosmic flower opening in the morning mist of the Milky Way, the long axis of the cross being the flower's stamen, and the haloes its petals.
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