Comments on the Vanguard 3 magnetic field data and analysis

Abstract

The principal results of the Vanguard 3 magnetic field experiment are summarized in a report and a paper [Cain et al., 1962 a, b]. Since some of the material presented in these documents has been used by several authors, it is worth while to clarify a few points and to report a modification indicated by a later analysis. The Vanguard 3 report gives a series of 63 spherical harmonic coefficients fitted to the data themselves by the iterative procedure of Jensen and Cain [1960] (reviewed by Heppner [1964]). This field, designated Vanga, used g• and h• • to n --m --7 and gave an rms deviation from the data of 21 7-The data selected for this fit were the 2797 observations given by Cain et al. [1962a] as L --0 (--best data), excluding four such observations with residuals (measured F-computed F) over 100 7. These observations were those recorded at Blossom Point, Maryland, on October 4, 1959, at Oh 47m 23s, Oh 47m 37s, 19h 50m 11s and 19h 50m 29s. In the Vanguard 3 report we

Magnetometers for space research

“…A more serious problem in the interpretation of data was due to uncertainties in the satellite spatial position. This satellite data provided accurate tests of the spherical harmonic representation of the geomagnetic field (Cain and Hendricks, 1964).…”

Geomagnetic models from satellite surveys

“…Cain and Hendricks (1968) 1940 GSFC(4/64) Cain et al (1965Cain et al ( ) 1945Cain et al ( -1964Cain et al ( 1959 GSFC(9/65) Hendricks and Cain (1966); Cain (1966) 1965. 8-1967.7 1967 -27 POGO(3/68) .8-1967.9 1967 POG0(10/68) Cain and pael (1968) 1965.8-1968.4 1967 -27 POGO(8/69) Cain and Sweeney (1970) respectively.…”

“…The first attempt to create a field model from only total field satellite observations was made by Cain et al (1962) and Cain and Hendricks (1964) in analyzing the Vanguard 3 data. In an attempt to organize these satellite data to study time variations, it was noted by Heppner et al (1960) that even the best recent models based on the analysis of magnetic charts (finch and Leaton, 1957;Jensen and Whitaker, 1960) were inadequate.…”