Gunther Können, who has produced a decent number of halo papers, has put his works on-line. These are found in the atmospheric optics section of his web page ( 1 ). Among others, there is an article about subsun on Mars (right photo), as photographed in 2006 by Mars Global Surveyor (left photo). Also, the extensive work on halo systematics, “A general setting for halo theory” by Tape and Können, is available.
left – NASA/JPL-Caltech/Corby Waste
right – NASA/JPL/Malin Space Science Systems