Letter | Published:

A Ready Method for finding Eccentric Dipole Time

Naturevolume 199pages12791280 (1963) | Download Citation



ECCENTRIC geomagnetic dipole1 time at an observatory (O) is defined for present purposes as the difference in eccentric dipole longitude (ɛ′) of the Sun (as distinct from the sub-polar point) and the observatory being measured eastwards from the Sun to the observatory, that is: Elsewhere2,3 it has been shown by different approaches that tecc. runs parallel to ordinary geomagnetic time (a centric system) differing by a constant C0, which is a characteristic of the observatory for the particular epoch of the Earth's magnetic field. Thus, also : where ɛ represents geomagnetic longitude. where3: X=−0.0577, Y=0.0320, Z=0.0184 for epoch 1955.0 and (θ0, ɛ0) are geographic co-ordinates of the observatory.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Parkinson, W. D., and Cleary, J., Geophys. J., Roy. Astro. Soc., 1, 346 (1958).

  2. 2

    Simonow, G. V. (to be published).

  3. 3

    Cole, K. D., Austral. J. Phys., 16 (in the press).

  4. 4

    Brice, N., and Ungstrup, E., Nature, 198, 874 (1963).

  5. 5

    Bond, F. R., and Jacka, F., Austral. J. Phys., 15, 261 (1962).

  6. 6

    Hultqvist, B., J. Atmos. Terr. Phys., 24, 17 (1961).

Download references

Author information


  1. Antarctic Division, Department of External Affairs, Melbourne

    • K. D. COLE
    •  & G. V. SIMONOW


  1. Search for K. D. COLE in:

  2. Search for G. V. SIMONOW in:

About this article

Publication history

Issue Date




By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.