Apparent Places of Fundamental Stars

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APFS ( A pparent P laces of F undamental S tars ) is an astronomical yearbook for astrometry and geodesy , which contains the exact apparent star locations for about 1600 fundamental stars and every tenth day of the year, for the cushions even for every day.

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The publisher is the Astronomical Computing Institute (ARI) in Heidelberg. Up to the year 2000 it appeared - about a year in advance - in book form with about 400 pages including auxiliary tables, now only a brochure with about 50 of the brightest stars is printed. The main part of the work is available on the Internet (see web link).

The ephemeris of the stars are calculated for every tenth Upper Culmination in Greenwich (ten sidereal days). This table interval is common for astronomical time and length determinations and is narrow enough that a linear interpolation of the star coordinates is sufficient for most applications . For the circumpolar stars, on the other hand, the table interval is shortened to one sidereal day , because otherwise the changes in the right ascension and the short-period nutation become non-linear.

The interpretation of the tables goes back to the Berlin Astronomical Yearbook , which also published the earlier fundamental catalogs FK3 and FK4 . Today's data are based on the modern FK6 , the ephemeris calculation on the international formula and reference system of the International Astronomical Union (IAU).

Web links