Comparison of the Carlsberg optical references frame with the International celestial reference frame J/A+A/312/1031 J/A+A/312/1031 Positions & proper motions of radio stars Comparison of the Carlsberg optical references frame with the International celestial reference frame R W Argyle O H Einicke J D H Pilkington L V Morrison C Fabricius L Helmer Astron. Astrophys. 312 1031 1996 1996A&A...312.1031A I/213 : CMC8 (8th Carlsberg Meridian Catalog, 1994) I/205 : CMC7 (7th Carlsberg Meridian Catalogue, 1993) I/189 : CMC6 (6th Carlsberg Meridian Catalogue, 1992) I/170 : CMC5 (5th Carlsberg Meridian Catalogue, 1991) I/147 : CMC4 (4th Carlsberg Meridian Catalogue, 1989) Nebulae Positional data astrometry references frames The optical positions of 63 extragalactic nebulae measured in the frame defined by the annual series of Carlsberg Meridian Catalogues Nos 1-8 are compared with their VLBI radio positions in the International Celestial Reference Frame. The differences between these radio and optical positions are interpreted as showing the global distortion of the Carlsberg optical frame, which is linked to that of the FK5. North of the equator the Carlsberg optical frame is within 0.05" of the ICRF; but south of the equator it deviates by 0.07" in right ascension and 0.10" in declination. The general form of the deviations follow those of the FK5, which are revealed in a recent comparison of FK5 with a preliminary version of the Hipparcos catalogue (H30).
Carlsberg optical positions of ICRF sources and differences, radio minus optical Name Name of radio source (IAU nomenclature) --- RAh Right ascension (2000) h RAm Right ascension (2000) min RAs Right ascension (2000) s DE- Declination sign --- DEg Declination (2000) d DEm Declination (2000) arcmin DEs Declination (2000) arcsec Nplate Number of plates --- DRA Delta RA (radio-optical) arcsec DDE Delta DE (radio-optical) arcsec Carlsberg optical positions and proper motions of radio stars Name Name of radio star --- RAh Right ascension (2000) h RAm Right ascension (2000) min RAs Right ascension (2000) s pmRA Proper motion in right ascension s/yr EpRA-1900 Epoch of RA (1900+) yr DE- Declination sign --- DEd Declination (2000) deg DEm Declination (2000) arcmin DEs Declination (2000) arcsec pmDE Proper motion in declination arcsec/yr EpDE-1900 Epoch of DE (1900+) yr DRA Delta RA(radio-optical) arcsec DDE Delta Dec(radio-optical) arcsec Patricia Bauer CDS 1996Mar11R.W. Argyle, <merlp@ast.cam.ac.uk> J_A+A_312_1031.xml