where might i find good posters of
star clusters and nebulae
volcanoes
wildflower meadows
light-ripple patterns, as seen in overhead shot of sunlit swimming pools [theres some examples on the lower half of the page/link below to show you exactly what i mean--theyre on corbis website, but i havnt yet worked out if they sell posters, or whether its only for advertising etc]
http://pro!.corbis!.com/search/searchFrame!.!.!.Www@QuestionHome@Com