21521+2748
- Unique Name: 21521+2748HO 171
- RA: 21 52 08.95
- Dec: +27 48 02.2
- Discoverer: HO
- Discoverer Number: 171
- Components:
- First year: 1884
- Last year: 2010
- Observations: 56
- First position angle: 359
- Last position angle: 342
- First separation: 0.6
- Last separation: 0.7
- Mag first component: 9.36
- Mag second component: 9.5
- Spectral type: A3
- Primary proper motion RA: 13
- Primary proper motion DEC: 4
- Secondary proper motion RA: 13
- Secondary proper motion DEC: 4
- Durchmusterung: +27 4184
- Notes: