The morphology and brightness of the zodiacal light and gegenschein

Abstract

A cooled CCD camera with 385 × 576 pixel has been used, in conjunction with a 16-mm fish-eye lens, to construct an isophot map of the zodiacal light and the gegenschein. The axis of symmetry of the zodiacal light at westerly elongations has been measured out to ε⊙ = 80° and found to be significantly south of the ecliptic plane and the axis of the invariable plane. A considerable north-south asymmetry in the intensity distribution was also found. The position and excess brightness of the gegenschein have also been measured. Its longitude is at the antisolar point within the limit of measurement, its centroid is 2°.5±0°.5 south of the ecliptic and its excess brightness is 40 ± 5 S10 units.