 Stars that are at least sometimes visible to the unaided eye have their apparent magnitude (6.5 or brighter) highlighted in blue.Note that even the most luminous stars are much less luminous than the more luminous persistent extragalactic objects, such as quasars.For example, 3C 273 has an average apparent magnitude of 12.8 (when observing with a telescope), but an absolute magnitude of −26.7.