The Hipparcos Catalog & HIP Numbers
How a 1990s space mission became the stars’ identity card — and how it relates to Gaia.
Hipparcos was an ESA astrometry satellite (1989–1993) that measured the positions, distances (parallaxes) and motions of 118,218 stars to thousandths of an arcsecond. Its HIP numbers are still a universal star identifier — the HIP 7097 or HIP 49669 on your certificate comes from here.
What a HIP number looks like
HIP numbers are plain sequence entries in the Hipparcos catalog: HIP 49669 is Regulus in Leo; HIP 7097 is another star genuinely sold on our site. The numbers carry no meaning by themselves — but they point to exact positions.
Hipparcos vs. Gaia
- Hipparcos (1997)
- 118,000 stars, to ~0.001 arcsecond
- Gaia (today)
- over a billion stars, far sharper — its successor
- Our catalog
- HYG-based (Hipparcos inside); brightness/color cross-checked with Gaia
Why your star has several numbers
One star appears in many catalogs: HIP in Hipparcos, a source ID in Gaia, and often a traditional name in its constellation. Your certificate prints both your Star ID and the catalog IDs so you can verify it anywhere.