20123+3451
- Unique Name: 20123+3451AG 249AB
- RA: 20 12 18.31
- Dec: +34 51 10.7
- Discoverer: AG
- Discoverer Number: 249
- Components: AB
- First year: 1896
- Last year: 2012
- Observations: 12
- First position angle: 133
- Last position angle: 132
- First separation: 34.6
- Last separation: 32.6
- Mag first component: 7.96
- Mag second component: 10.78
- Spectral type: K2V
- Primary proper motion RA: 16
- Primary proper motion DEC: -7
- Secondary proper motion RA: 2
- Secondary proper motion DEC: -2
- Durchmusterung: +34 3910
- Notes: