Reference frame

The Fourth Fundamental Catalogue (FK4)

The predecessor of FK5, a fundamental star frame referred to the equinox and epoch B1950. Positions given in the FK4 (B1950) system must be precessed and rotated to be compared with modern J2000/ICRS coordinates — a common source of small errors when working with older catalogues and charts.

Highlights

›The B1950 bright-star frame that FK5 replaced

The Fifth Fundamental Catalogue (FK5)
The B1950 Epoch

Across the reference systems

The Fifth Fundamental Catalogue (FK5)

Knowledge connections

Associated withThe Fifth Fundamental Catalogue (FK5)
Associated withThe Fifth Fundamental Catalogue (FK5)
Associated withThe B1950 Epoch

Sources

Facts on this topic will be cited from these primary and reference sources.

IAUInternational Astronomical Union
Official naming, definitions, constellation boundaries, and astronomical nomenclature.

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The Fourth Fundamental Catalogue (FK4)

Highlights

Related systems & concepts

Across the reference systems

Knowledge connections

Sources

The Fourth Fundamental Catalogue (FK4)

Highlights

Related systems & concepts

Across the reference systems

Knowledge connections

Sources