21156+3715
- Unique Name: 21156+3715HO 285AB
- RA: 21 15 34.01
- Dec: +37 15 08.5
- Discoverer: HO
- Discoverer Number: 285
- Components: AB
- First year: 1888
- Last year: 2002
- Observations: 5
- First position angle: 25
- Last position angle: 23
- First separation: 8.6
- Last separation: 9.2
- Mag first component: 7.75
- Mag second component: 12.9
- Spectral type: B4V
- Primary proper motion RA: 1
- Primary proper motion DEC: -4
- Secondary proper motion RA:
- Secondary proper motion DEC:
- Durchmusterung: +36 4492
- Notes: