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International Earth Rotation and Reference Systems Service

ICRF2 - The 2nd realization of the International Celestial Reference Frame

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).

Number of objects: 3414 

AccuracyThe uncertainties in the coordinates are provided for each object and are given in the following ranges:
Right Ascension [s]0.00000273 - 0.00252791
Declination ["]0.0000413 - 0.0427226
Updates

Updates to the ICRF are released at irregular intervals, typically every few years.

Public access
Format

For a detailed description of the format, refer to the contents of the data file.

Documentation
  • IERS Technical Note No. 35
  • Fey, A. L.; Gordon, D.; Jacobs, C. S.; Ma, C.; Gaume, R. A.; Arias, E. F.; Bianco, G.; Boboltz, D. A.; Böckmann, S.; Bolotin, S.; Charlot, P.; Collioud, A.; Engelhardt, G.; Gipson, J.; Gontier, A.–M.; Heinkelmann, R.; Kurdubov, S.; Lambert, S.; Lytvyn, S.; MacMillan, D. S.; Malkin, Z.; Nothnagel, A.; Ojha, R.; Skurikhina, E.; Sokolova, J.; Souchay, J.; Sovers, O. J.; Tesmer, V.; Titov, O.; Wang, G.; Zharov, V. (2015). The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry. The Astronomical Journal, 150(2), 58. https://doi.org/10.1088/0004‑6256/150/2/58
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