20521+4923
- Unique Name: 20521+4923ES 811
- RA: 20 52 05.96
- Dec: +49 21 49.1
- Discoverer: ES
- Discoverer Number: 811
- Components:
- First year: 1909
- Last year: 2010
- Observations: 12
- First position angle: 138
- Last position angle: 159
- First separation: 2.0
- Last separation: 1.4
- Mag first component: 10.34
- Mag second component: 10.43
- Spectral type: G0
- Primary proper motion RA: -43
- Primary proper motion DEC: -16
- Secondary proper motion RA: -43
- Secondary proper motion DEC: -16
- Durchmusterung: +48 3230
- Notes: