This data set contains the 198 coefficients of the POGO (3/68) spherical harmonics model of the Earth's main (core) magnetic field. The coefficients are for epoch 1960.0 and extend up to degree and order 9 in the constant and first derivative terms. The model is based on field strength data obtained with the (Polar) Orbiting Geophysical Observatory (POGO or OGO) satellites from October 12, 1965, to August 2, 1967 (mostly OGO 2, some early OGO 4 data). Altogether 22,252 data points were used in establishing POGO (3/68). The model represents the OGO data much better than the older GSFC (12/66) model and was submitted as candidate for the International Geomagnetic Reference Field (see Cain and Langel, 1971).
J. C. Cain and S. J. Cain, Derivation of the International Geomagnetic Reference Field, IGRF (10/68), Goddard Space Flight Center, Report X-612-68-501, Greenbelt, Maryland, 1968.
J. C. Cain and R. A. Langel, Geomagnetic Survey by the Polar-Orbiting Geophysical Observatories, in: World Magnetic Survey 1957-1969, A. J. Zimuda (ed.), 65-75, IAGA Bulletin, No. 28, International Union of Geodesy and Geophysics, Paris, 1971.