Cometary Appearance Of Venus

The famed astronomer Johann Maedler first recorded strange brushes of light emanating from the bright limb of Venus. Two luminous fans opening sunward gave the planet the appearance of a multitailed comet. Maedler made this curious observation on April 7, 1833; and it has come to be known as the Maedler Phenomenon. If it were not for Maedler's fame as an honest, meticulous observer, the event would have been fogotten long ago. A similar observation was made by Gadbury in 1686. The only explanation for the phenomenon offered so far involves some sort of obscure type of halo or sun-pillar effect.

(Baum, Richard; "The Maedler Phenomenon," Strolling Astronomer, 27:118, 1978.)