21009+4730
- Unique Name: 21009+4730BU 1290AB
- RA: 21 00 56.09
- Dec: +47 29 37.3
- Discoverer: BU
- Discoverer Number: 1290
- Components: AB
- First year: 1898
- Last year: 2010
- Observations: 17
- First position angle: 16
- Last position angle: 33
- First separation: 3.9
- Last separation: 8.6
- Mag first component: 10.09
- Mag second component: 10.65
- Spectral type:
- Primary proper motion RA: 10
- Primary proper motion DEC: 10
- Secondary proper motion RA: 47
- Secondary proper motion DEC: 45
- Durchmusterung: +46 3142
- Notes: L
