Letter | Published:

Solar Effects in the Motion of Vanguard


A NEW analysis which I have carried out of the complicated period changes of Satellite 1958 β2 (Vanguard) shows a correlation with three solar effects: (1) the hour angle of the Sun as reckoned from the perigee point of the orbit; (2) the 27-day variations in solar activity discovered by Jacchia1; (3) the total daily solar insolation at the latitude of perigee.

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  1. 1

    Jacchia, L. G., Harvard Announcement Card 1391 (Feb. 5, 1958).

  2. 2

    Jacchia, L. G., Smithsonian Obs. Spec. Report No. 20 (Jan. 5, 1959); Nature, 183, 526 (1959).

  3. 3

    Jastrow, R., and Pearse, C. A., J. Geophys. Res., 62, No. 3 (1957).

  4. 4

    Spitzer, L., ‘;The Atmospheres of the Earth and Planets’, Ed., G. P. Kuiper, 211 (Univ. of Chicago, 1951).

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