Supplement star

As a supplement stars (Engl. Supplement ) are fixed stars with precisely measured Sternörtern referred to in a the next few years fundamentals catalog to include.

The summary in separate lists or files also serves to stimulate coordinate measurements - especially those of an absolute character.

A fundamental catalog serves to define the celestial (Zälestic) coordinate system for the coordinates right ascension (abbreviated RA or α ) and declination ( Dec or δ ) as precisely as possible .

Such precise coordinate frames (see also reference system ) are required by astronomy and geodesy for various calculations on earth, in the solar system and in interstellar or intergalactic space . An externally defined inertial system is also necessary for physics and the time systems .

The supplement catalog FK4sup was considered a suitable addition to the then valid FK4 for the period between 1964 and 1988 . It initially comprised almost 1,000 stars, later over 3,000, which were still somewhat less accurate.
Such additions are necessary on the one hand to homogenize the star distribution . on the other hand, for example for astrolabes or zenith cameras , for whose measurements the 1500 fundamental stars were too few (around 1 star on 30 square degrees).

The following table shows some characteristic values ​​of the fundamental systems FK3 to FK5 , as well as the two supplement catalogs valid in the meantime.

labeling

Short name	Star number	Official name	publ.	Measurement
				Places	Own movements
FK3	873	Third fundamental catalog	1937	1912-1915
FK3sup	+662	(Additional stars, Volume II)	1938	Ø 1913	1845-1930
FK4	1535	Fourth Fundamental Catalog	1963	Ø 1950
FK4sup	1111	Supplement Stars FK4 / 5	~ 1965
FK5	1535	Fifth Fundamental Catalog	1988	Ø 1975
FK5sup	3117	Supplement Stars of FK5	1991
Hipp.	118000	Hipparcos catalog	1998	1989-1993	1989-1993

Note: The Hipparcos is not a fundamental catalog in the strict sense, but has only been precisely adapted to the FK5 system and has "stiffened" it.