Netiquette ba form, I'm going to reply to my own post. > path lengths is important. So a knowledge of path lengths versus > magnitude and radiant distance is needed. There have been papers on > this in the BAC (is that in the list of abbreviations Lew?). One reference I had in mind is: Kresakova, M., 1977, Bull Astron. Inst. Czech, 28, 340. Malcolm