But the comet is heading into the Southern Hemisphere skies and may no longer be visible from the United States, Hergenrother said. It will come back into our Northern Hemisphere skies at the end of June after it swings under the Sun. By then, it might be visible to the naked eye, though that is not certain. And no one expects it to put on any kind of show like Hale-Bopp or other popular comets past. Sudden brightening The brightness of stars and other celestial objects is measured on a scale of apparent brightness.
Smaller numbers are brighter and negative numbers are the brightest.
Magnitude 6.0 is the faintest object visible to the naked eye under dark skies. The brightest star is minus 1.4 on the scale, and Venus is minus 4.4 at its brightest. Hergenrother and his colleagues have been watching this newly found comet for months using a University of Arizona telescope. It was a typical, rather mundane target that was not expected to brighten much. The jump in visual brightness occurred March 25-26, when it rose from an indistinct magnitude 12 to 10.7.