FK5
The FK5 , full title: Fifth Fundamental Catalog (fifth fundamental catalog), is the most important fundamental catalog of astronomy of the last 20 years and defined the celestial (celestial) coordinate system until about 2010 . The FK6 replaced the FK5 since 2000. FK6 contains fewer stars, but measured much more precisely than in FK5. FK5 has served astronomy and geodesy since 1988 as the most precise implementation of a reference system for the coordinates right ascension and declination . With its underlying constants, it also provided a precise model for tasks in the planetary system , as well as an extensive inertial system for extragalactic astronomy.
The FK5 contains 1535 fundamental stars (ie stars measured to at least 0.05 ″) and 3117 supplement stars (supplement, publ. 1991). These star locations were determined from dozens of previous catalogs and with new relative and absolute methods of astrometry . The measurements from different epochs were transformed to the two standard epochs B1950.0 and J2000.0 .
The 1535 stars go back to the previous catalog FK4 (Heidelberg 1963) and to another 3115, somewhat less precisely defined stars. Overall, they have a nearly homogeneous distribution and accuracy (better than 0.05 ″) over the entire sky.
The system also contains precise proper motions of each star. They are partly based on measurements up to 100 years ago, so that the positions can be converted a few decades into the future and into the past. They relate with great accuracy to a stationary ("inertial") system. It only had to be changed by about 0.01 ″ when transitioning from the FK4.
Short name | Number of stars | title | Published | Measurement places | Measurement of own movements | Overlap |
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Auwers, A., 1879 | 539 | Fundamental catalog for zone observations on the Nördl. sky | 1879 | Ø 1860 | ≈1850-1870 | up to dec. = −10 ° Note 1 |
Peters, J., 1907 | 925 | New FK Berliner Astr. Yearbook based on the principles of Auwers | 1907 | Ø 1880 | 1745-1900 | up to dec. = −89 ° |
FK3 | 873 | Third fundamental catalog of the Berlin Astronomical Yearbook | 1937 | 1912-1915 | from here over the whole sky, with epochs 1900, 1950, 2000 |
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FK3sup | 662 | (Additional stars, Volume II) | 1938 | Ø 1913 | 1845-1930 | |
FK4 | 1,535 | Fourth Fundamental Catalog | 1963 | Ø 1950 | ||
FK4sup | 1,111 | Supplement Stars FK4 / 5 | ≈1965 | |||
FK5 | 1,535 | Fifth Fundamental Catalog | 1988 | Ø 1975 | ||
FK5sup | 3.117 | Supplement Stars of FK5 | 1991 | |||
Hipp. Note 2 | 118,000 | Hipparcos catalog | 1998 | 1989-1993 | 1989-1993 | |
FK6 | 4,150 | Sixth Catalog of Fundamental Stars | 1999, 2000 | Ø 1992 |