Photometric Observations of 5577 ? and 6300 ? Airglow During the I.G.Y.

Abstract

Twenty.one months' observation of the airglow from near Sydney, Australia, shows that (a) aurorae are detected 10° above the southern horizon at 6300 A whenever the magnetic disturbance index (K) reaches 5 but K must reach 7 before detection is certain at 5577 A; (b) the 6300 A zenith intensity increases rapidly with K once this equals or exceeds 4, but the 5577 A zenith intensity is independent of magnetic disturbance; (c) the zenith intensity of 5577 A tends to be a maximum at 03 hr local time; (d) the zenith intensity of 6300 A drops rapidly from dusk till 01 hr and then rises till dawn.