When is the best time to observe Tau Sagittarii?

Tau Sagittarii is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is Tau Sagittarii located in the sky?

Tau Sagittarii lies in the constellation Sagittarius at right ascension 19h 07m and declination -27° 40′.

What telescope do I need to see Tau Sagittarii?

At magnitude 3.3, Tau Sagittarii is visible to the naked eye from dark skies, easy in any binoculars.

Tau Sagittarii — Star in Sagittarius

Magnitude 3.3^m Star Sagittarius (Sgr) Visible

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About Tau Sgr

Description

Tau Sagittarii is an orange giant of spectral type K1III at magnitude 3.32 in Sagittarius. Located about 120 light-years from Earth, it has a surface temperature of about 4,600 K and a luminosity roughly 90 times solar. It lies in the handle of the Teapot asterism of Sagittarius.

Observing Tips

Tau Sgr is part of the Teapot asterism of Sagittarius, forming part of the handle on the northern side. It appears as a warm orange star among the rich star clouds of the summer Milky Way. Best observed from July through September when Sagittarius is at its highest in the evening sky.

History

Tau Sagittarii has no widely used traditional name. It became briefly famous in 1977 as the origin direction of the 'Wow! signal' — a strong narrowband radio signal detected by Ohio State University's Big Ear radio telescope that lasted for 72 seconds and has never been explained or detected again.

Fun Facts

The famous Wow! signal of 1977 — the strongest candidate ever detected for an extraterrestrial radio transmission — came from the direction of Tau Sgr. Despite decades of follow-up observations pointing at this star, the signal has never recurred, and its origin remains one of astronomy's great unsolved mysteries.