The International Celestial Reference Frame (ICRF) realizes an ideal reference system, the International Celestial Reference System (ICRS), by precise equatorial coordinates of extragalactic radio sources observed in Very Long Baseline Interferometry (VLBI) programmes.
| Content | This dataset provides the equatorial coordinates of extragalactic radio sources observed at J2000.0 using Very Long Baseline Interferometry (VLBI) across the S/X, K, and X/Ka frequency bands, with the S/X-band remaining the conventional reference for geodesy, Earth orientation, and satellite orbit determination. | ||
| Number of objects | |||
| S/X | 4536 | ||
| K | 824 | ||
| X/Ka | 678 | ||
| Accuracy | The uncertainties in the coordinates are provided for each object and are given in the following ranges: | ||
| Right Ascension [s] | Declination ["] | ||
| S/X | 0.00000202 - 0.00899265 | 0.0000303 - 0.2507685 | |
| K | 0.00000245 - 0.00086595 | 0.0000613 - 0.0118579 | |
| X/Ka | 0.00000291 - 0.00446018 | 0.0000470 - 0.0735481 | |
| Updates | updates to the ICRF are released at irregular intervals, typically every few years. | ||
| Public access | IERS ICRS Product Centre (Observatoire de Paris): https://hpiers.obspm.fr/icrs-pc/icrf/index.php IERS ICRS Product Centre (USNO): https://crf.usno.navy.mil/ICRF3 IERS Data Center: https://datacenter.iers.org/products/reference-systems/celestial/icrf3/ | ||
| Format | For a detailed description of the format, refer to the contents of the data file. | ||
| Documentation | Charlot, P., Jacobs, C. S., Gordon, D., Lambert, S., de Witt, A., Böhm, J., Fey, A. L., Heinkelmann, R., Skurikhina, E., Titov, O., Arias, E. F., Bolotin, S., Bourda, G., Ma, C., Malkin, Z., Nothnagel, A., Mayer, D., MacMillan, D. S., Nilsson, T., & Gaume, R. (2020). The third realization of the International Celestial Reference Frame by very long baseline interferometry. Astronomy & Astrophysics, 644, A159. https://doi.org/10.1051/0004-6361/202038368 | ||
| Product center | IERS ICRS Centre | ||
