This lovely double star at the head of Cygnus the Swan shows off contrasting colors, making it a summertime favorite.
- Albireo (β Cygni), located in the constellation Cygnus, is a double star system easily observable in the eastern sky after sunset during summer months.
- Albireo’s components exhibit contrasting colors, typically described as gold and blue, with magnitudes of 3.4 and 5.1 respectively, though individual perception of these colors may vary.
- While appearing as a single star to the unaided eye, telescopic observation reveals the binary nature of the brighter component, although its sub-components are not easily resolved.
- The provided text includes sunset and moonrise times (8:05 PM and 8:06 PM respectively) for a specific location (40° N 90° W) and indicates the moon phase as a 99% waxing gibbous.
Tonight, we’re visiting a summertime favorite: the double star Albireo in Cygnus the Swan. Already 60° high in the east an hour after sunset, Albireo — also cataloged as Beta (β) Cygni — marks the head of Cygnus, sitting opposite the brighter star Deneb (Alpha [α] Cyg) at the Swan’s tail. Around 9 P.M. local daylight time, look high in the east to find magnitude 0.0 Vega, Lyra’s brightest star. Drop your gaze about 15.5° below Vega and you’ll land right on 3rd-magnitude Albireo.
Although appearing as one star to the naked eye, a small telescope will reveal this is not one but two stars, separated by 34”. Their lovely contrasting colors of gold and blue are what make them such a popular target. The brighter (golden) star shines at magnitude 3.4, while its fainter (bluer) companion has a magnitude of 5.1. (That brighter star is actually itself two stars, though they cannot be easily separated in a telescope.)
Although most observers do see these stars as yellow and blue, not everyone picks up these hues the same way. Every eye is different, so you might see them as slightly — or very! — different shades. Take some time to enjoy them and consider how you would describe the colors of these two stars.
Sunrise: 6:05 A.M.
Sunset: 8:05 P.M.
Moonrise: 8:06 P.M.
Moonset: 5:01 A.M.
Moon Phase: Waxing gibbous (99%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
For a look ahead at more upcoming sky events, check out our full Sky This Week column.
