Letter | Published:

Magnetic Field Associated with a Great Solar Flare


AN unusually large solar flare, of intensity 3+, was observed at Mount Wilson on July 16, 1959. The flare was in an active region centered on the spot group at approximately 18° N., 29° W. It showed a predominantly S-shaped or double spiral configuration, with marked variations of relative intensity in its various parts. Visual observations of the spectrum showed that the flare commenced abruptly between 21.19 and 21.24 U.T.; maximum was between 22.01 and 22.13 U.T. Lines of Ca II, Na, He and H were observed to be in emission for more than 1 hr.; the width of the Hα emission was greater than 6 A. Emission persisted in the lines of Ca II and of H until after observations were terminated at 01.00 U.T. on July 17.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Babcock, H. W., Astrophys. J., 118, 387 (1953).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading


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.