Table 5.
Statistics of the reference systems of observational data extracted from the sources.
| N | N% | Ng | Ng% | Years | |||
|---|---|---|---|---|---|---|---|
| rfs | C | obs | |||||
| B1899 | ? | PAS | 42 | 0.17% | 21 | 0.52% | 1899–1901 |
| B1905 | ? | PAS | 12 | 0.05% | 6 | 0.15% | 1905–1905 |
| B1949 | K | ABS | 14 | 0.06% | 3 | 0.07% | 1949–1949 |
| + | DIF | 972 | 3.89% | 44 | 1.09% | 1985–1994 | |
| ? | ABS | 30 | 0.12% | 12 | 0.30% | 1967–1987 | |
| B1950 | DIF | 98 | 0.39% | 47 | 1.16% | 1949–1987 | |
| I | DIF | 34 | 0.14% | 12 | 0.30% | 1977–1984 | |
| p | DIF | 16 | 0.06% | 6 | 0.15% | 1982–1985 | |
| + | DIF | 150 | 0.60% | 4 | 0.10% | 1997–1997 | |
| ? | ABS | 362 | 1.45% | 32 | 0.79% | 1990–2004 | |
| DRD | 6 | 0.02% | 1 | 0.02% | 1999–1999 | ||
| L | ABS | 116 | 0.46% | 13 | 0.32% | 2013–2015 | |
| U | ABS | 1798 | 7.19% | 29 | 0.72% | 2012–2018 | |
| V | ABS | 2018 | 8.07% | 76 | 1.88% | 2006–2019 | |
| c | ABS | 86 | 0.34% | 5 | 0.12% | 2004–2009 | |
| f | ABS | 108 | 0.43% | 53 | 1.31% | 1986–1993 | |
| g | ABS | 3092 | 12.37% | 1141 | 28.19% | 1963–2014 | |
| ICRS | l | ABS | 292 | 1.17% | 145 | 3.58% | 1998–2000 |
| m | ABS | 6 | 0.02% | 1 | 0.02% | 2002–2002 | |
| o | ABS | 454 | 1.82% | 77 | 1.90% | 2002–2014 | |
| p | ABS | 460 | 1.84% | 24 | 0.59% | 1993–1998 | |
| DIF | 1866 | 7.47% | 43 | 1.06% | 1993–1998 | ||
| q | ABS | 1950 | 7.80% | 124 | 3.06% | 1992–2018 | |
| r | ABS | 4550 | 18.20% | 112 | 2.77% | 1996–2013 | |
| s | ABS | 12 | 0.05% | 2 | 0.05% | 2004–2004 | |
| u | ABS | 170 | 0.68% | 42 | 1.04% | 2009–2012 | |
| v | ABS | 78 | 0.31% | 20 | 0.49% | 2008–2009 | |
| / | DIF | 414 | 1.66% | 64 | 1.58% | 1903–1991 | |
| PAS | 5620 | 22.48% | 1813 | 44.79% | 1847–1942 | ||
| TOD | ? | PAS | 164 | 0.66% | 75 | 1.85% | 1902–1920 |
| C | DRD | 6 | 0.02% | 1 | 0.02% | 1970–1970 | |
Notes. rfs and obs are the items for reference systems and observables used in OCNS2019, respectively. C is the MPC code of the astrometric catalog, astCat. N and N% are the number and percentage of observed coordinates, respectively, and Ng and Ng% are those of observation nights.
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