Star profile
Tau Ophiuchi
Binary systemWhat is Tau Ophiuchi
Tau Ophiuchi is a multiple system 167 light-years away: two yellow-white stars orbiting each other every 257 years in a highly elongated ellipse, with a faint third component sitting a hundred arcseconds out. The primary also hides a small dwarf companion that circles it every 186 days. The visual orbit has been patiently tracked since 1835 with over six hundred observations, a near two-century-long conversation between astronomers.
Where it is and when to see it
Tau Ophiuchi lies in the southern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is June, when it culminates around midnight.
- From London it culminates about 30° above the horizon.
- From New York it culminates about 41° above the horizon.
- From Sydney it culminates about 64° above the horizon.
It can be seen from anywhere south of 82° N.
It ranks no. 34 in brightness among the 88 stars of Ophiuchus in our catalogue. To find it, start from Rasalhague, the brightest: it lies about 22° away (a fist at arm's length covers about 10°).
The light you see today left it about 170 years ago.
It opens in your browser. Free, no account, nothing to install.
Leave your signature on Tau Ophiuchi
Your name and a message go up on the map for everyone to read. Signing is free.
Without a lock, someone else can replace your signature. How the lock works
We'll ask for an email to confirm it's you, no password.
A public signature from a real person. The chosen name is a symbolic denomination within Stelvia, with no official standing or IAU recognition: the sky is not for sale and belongs to no one.
Astronomical data for Tau Ophiuchi
- Constellation
- Ophiuchus
- Apparent magnitude
- 4.77
- Distance
- 167.5 light years
- Coordinates (J2000)
- RA 270.771° · Dec -8.180°
- Catalogue
- HIP 88404 · HD 164764
A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.
Other stars in Ophiuchus
Ophiuchus has 88 stars in Stelvia's catalogue. Here are a few of them.
- RasalhagueAlpha Ophiuchi2.08
- SabikEta Ophiuchi2.43
- Zeta Ophiuchi2.54
- 20 Ophiuchi4.64
- 71 Ophiuchi4.64
- 41 Ophiuchi4.72
- 51 Ophiuchi4.78
- 66 Ophiuchi4.79