The catalogues were matched sequentially in the order listed. Relevant object parameters were transferred to existing records and then new objects added.
| Step | GSC2 objects | Catalogue Matched | Catalogue Objects | Objects Matched | Objects Added |
|---|---|---|---|---|---|
| 1 | 945,443,930 | GAIA dr1 | 1,142,679,769 | 685,921,019 | 456,758,750 |
| 2 | 1,402,202,680 | APASS dr9 | 61,176,401 | 46,867,631 | 0 |
| 3 | 1,402,202,680 | UCAC5 | 107,758,513 | 107,758,513 | 0 |
| 4 | 1,402,202,680 | 2MASS | 496,911,362 | 449,162,648 | 47,748,714 |
| 5 | 1,449,951,394 | SDSS dr13 | 469,050,976 | 161,761,097 | 307,289,879 |
| 6 | 1,757,241,273 | VISTA VHS dr4 | 1,155,634,198 | ||
| 7 | VISTA VIKING dr2 | 46,270,162 | |||
| 8 | VST ATLAS dr3 | 105,132,174 | |||
