21121+4543
- Unique Name: 21121+4543BU 160BC
- RA: 21 12 09.28
- Dec: +45 41 21.1
- Discoverer: BU
- Discoverer Number: 160
- Components: BC
- First year: 1873
- Last year: 2011
- Observations: 14
- First position angle: 140
- Last position angle: 114
- First separation: 2.0
- Last separation: 6.5
- Mag first component: 11.4
- Mag second component: 11.6
- Spectral type:
- Primary proper motion RA: -1
- Primary proper motion DEC: -3
- Secondary proper motion RA: 5
- Secondary proper motion DEC: -5
- Durchmusterung:
- Notes: N
