| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus [1] | 
| Right ascension | 17h 18m 37.0s [2] | 
| Declination | +10° 51′ 52″ [2] | 
| Apparent magnitude (V) | 5.03 [3] | 
| Characteristics | |
| Spectral type | K4II-III [3] | 
| U−B color index | 1.89 [3] | 
| B−V color index | 1.55 [3] | 
| R−I color index | 0.83[ citation needed ] | 
| Astrometry | |
| Absolute magnitude (MV) | −0.86 [1] | 
| Other designations | |
| e Oph, 66 Her, BD+11 3156, SAO 102725, HD 156681, HR 6433 [2] | |
| Database references | |
| SIMBAD | data | 
e Ophiuchi (HD 156681) is a star in the constellation Ophiuchus near the border with Hercules, which it had been mistakenly catalogued 66 Herculis. [4] It has an apparent magnitude of 5.03.