М12 < М13 > М14 ...
Globular star cluster M13
Globular star cluster M13 or Great Globular Cluster in Hercules star cluster is in the constellation Hercules (Her).
Equatorial coordinates (epoch J2000):
Visual magnitude: 7,0m
Optimum magnification for a telescope with observations of M13, depending on the aperture of the telescope (D), is about D/2-D. Higher magnifications of course add details, but lead to a strong drop in the brightness of the image, making it difficult to observe.
Nikolay Kurdyapin, astro-map.com
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