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 | |||
| 2 | 1,402,202,680 | APASS dr9 | |||
| 3 | 1,402,202,680 | UCAC5 | |||
| 4 | 1,402,202,680 | 2MASS | |||
| 5 | 1,449,951,394 | SDSS | |||
| 6 | 1,757,241,273 | VISTA VHS dr4 | |||
| 7 | VISTA VIKING | ||||
| 8 | VST ATLASS | ||||
