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Star proper motion
From: Aubrey O´Callaghan
Date: 2001 Nov 20, 7:04 AM
From: Aubrey O´Callaghan
Date: 2001 Nov 20, 7:04 AM
I am astro navigation writing some software for my HP49G and have been looking for star proper motions for calculation of SHA. I have found a good website (http://www.alcyone.de/SIT/SIT_en.htm). However I have some questions about the proper motion. Looking up the proper motion of Sirius (http://www.alcyone.de/SIT/mainstars/SIT000499.htm) get some conflicting answers depending upon the source, which should be used to get the Nautical almanac equivalent ? I can live with the difference is the RA and the declination. However I find an order of magnitude of difference in the RA proper motion disconcerting. The Bright Star catalogue and the Washington Visual Double star catalogue give the same values but the SKY200 0 Master Star Catalog and Smithsonian Astrophysical Observatory Star Catalog give another value The SKY2000 Master Star catalogue references its source of proper motion to "The Bright Star Calalogue, yet gives a different answer to the Bright Star catalogue". I get similar results when I look up Procyon, so I don't believe in typo errors. Does anybody have an explanation ? Aubrey. The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) (Hoffleit+, 1991) Position (J2000) RA 6h 45min 8.9sec Dec -16 42' 58" Proper motion RA -.553 arcsec/a Dec -1.205 arcsec/a data from SKY2000 - Master Star Catalog (Myers+ 1997) Position (J2000) RA 6h 45 min 8.821sec Dec -16 42' 56.85" Proper motion -0.0385 arc/a Dec -1.205 arcsec/a data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990) Position (J2000) RA 6h 45min 8.917sec Dec -16 42' 58.11" Proper Motion -.0379 arcsec/a Dec -1.206 arecsec/a data from The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996) Position (J2000) RA 6h 45.1 Dec -16 43 min Proper Motion -0.553 arcsec/a Dec 0 arecsec/a