Blue-white subgiant · Ophiuchus
θ Ophiuchi
Also known as: θ Oph, HIP 84970
mag 3.3440 light-years
About
θ Ophiuchi is a blue-white subgiant of magnitude 3.3 in Ophiuchus, about 440 light-years away.
How to find it
- θ Ophiuchi is in the constellation Ophiuchus.
- Best evenings: around late July it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
- Where on Earth: it is seen well, at least 10° up, from south of 55° N.
When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.
What you will see
- EyesVisible from the suburbs on a clear night, but lost in bright city skies.
- Binoculars (10×50)A sharp point; binoculars bring out its colour and the fainter stars around it.
- Telescope (6–8 inch)Still a point of light at any magnification — stars are too far away to show a disc. Low in the sky, bright stars twinkle and flash colours.
Stars look the same in any instrument: brighter and sharper, but never bigger.
Facts
| Designation | θ Ophiuchi (θ Oph) |
|---|---|
| Hipparcos number | HIP 84970 |
| Type | Blue-white subgiant |
| Spectral type | B2IV |
| Colour | Blue-whiteB−V colour index −0.19 |
| Magnitude | 3.3The smaller the number, the brighter. |
| Distance | 440 light-yearsThe light you see left it around 1590. |
| Proper motion | 0.025″ per year across the sky |
| Constellation | Ophiuchus |
| Right ascension (J2000) | 17h 22m 00.6s |
| Declination (J2000) | −24° 59′ 58″ |
Sources and credits
Star data: HYG Database by David Nash, CC BY-SA 4.0. All data sources →