SCHWASSMANN-WACHMANN 1, COMET

comet discovered photographically by the German astronomers Friedrich Carl Arnold Schwassmann and Arthur Arno Wachmann in 1927. It has the most nearly circular orbit of any comet known (eccentricity 0.131) and remains always between the orbits of Jupiter and Saturn. It is also remarkable for explosion-like changes in its brightness, which sometimes increases by several magnitudes in a matter of hours.