Star Colors

A few comments about viewing star colors before we look at some individual gems.  Knowing what hue is supposed to be displayed for a given star actually helps see them.  If you happen to be near-sighted, trying looking at them with and then without your glasses.  A defocused image spreads the light out over a larger area of the retina activating more of its color receptors. Binocular are great for identifying hues since they provide a brighter image.  And defocusing them works the same way as removing glasses. Incidentally, the differing dues of stars is the result of temperature—not to composition, as generally believed.


Use your Scientifics Star & Planet Locator set for around 9 p.m. local time to identify each of our targets.  If you follow the curve of the Big Dipper’s handle downward you will come to the lovely golden-topaz sun Arcturus in the constellation Bootes. Continuing downward brings you to the icy-blue star Spica in Virgo.  Looking back and forth between the two stars reveals a definite color contrast.  Moving eastward in the sky from Spica we find low in the south the ruddy-orange supersun Antares in Scorpius.  Its name means “rival of Mars,” the so-called red planet. So three stars—each displaying obvious different celestial hues.  (Note that due to its low elevation above the horizon, when the air is turbulent Antares can look fiery-red, and even flicker and flash various colors. Other stars when rising and setting also exhibit this same kaleidoscopic behavior.)


Looking high nearly overhead in the sky is the radiant blue-white sapphire, Vega.  It (and the dazzling winter star Sirius—brightest of the entire celestial host) is the most bluish-looking jewel in the heavens.  Eastward of Vega, Deneb in Cygnus and Altair in Aquila are the most “white-looking” of all the bright stars.  But both have a slight tinge of blue. We’ve concentrated here on only the brightest stellar gems.  But among the fainter stars, every imaginable hue is to be found, among them blood-red, emerald-green, purple-violet, pale sapphire, and gold.  Leisurely sweeping the sky with binoculars on a dark moonless night will reveal many such unexpected sights, especially along the misty glow of the Milky Way.  As one writer from the past stated: “Every tint that blooms in the flowers of summer flames out in the stars at night.”  (Note: the colors of all the bright stars of every season are given on the back of the Star and Planet Locator.)



—James Mullaney

Former assistant editor at Sky & Telescope magazine & author of 10 books on stargazing. His latest, Celebrating the Universe!, is available from