Good Evening
Good Evening

Sky watch: Albireo's lovely color effect

Summer is a wonderful time for stargazing. Not only is the nighttime weather usually pleasant, but the sky also offers some remarkable sights.

Over many years as a celestial tour guide, I've discovered how many folks are surprised to learn that stars do not all appear the same, but actually display different colors. Those that appear white are hotter than those that are orange or red. And bluish stars are the hottest. Trying to see these hues can be quite a challenge, since the human eye's color receptors do not respond well in low light.

Star colors are subtle, and anyone with the slightest color blindness might miss them completely. But there is a place in the heavens where two very differently tinted stars lie side by side. Astronomers know this "binary star" as Beta Cygni, but its proper name is Albireo.

We can find Albireo within the Summer Triangle -- formed by the three bright stars Deneb, Vega and Altair -- high in the eastern sky after dark this week. It marks the head of Cygnus, the swan, also known as the Northern Cross.

With our unaided eyes, we see Albireo as a single star. But aim a small low-powered telescope in its direction, and you can resolve its light into that of two stars. In 1905, astronomy writer Agnes Clerke wrote the tints "golden and azure" gave perhaps "the most lovely effect of color in the heavens." Anyone peering at Albireo will agree.