The astronomy department (Sterrewacht Leiden) is the largest in the Netherlands and is internationally renowned, performing research in a wide range of astronomical disciplines.

In astronomical disciplines, a telescope qualifies as robotic if it makes those observations without being operated by a human, even if a human has to initiate the observations at the beginning of the night, or end them in the morning.

Clayton predicted a new astronomical discipline based on the relative abundances of the isotopes of chemical elements as they would condense in solids in "stardust", a component of Cosmic dust to be found later distributed within meteories.

His 1997 book, "The Whole Shebang," was an attempt to take it all in; but "Seeing in the Dark," on the same subject, is even more delightful and successful because Ferris has so artfully pinned its organization to the human experiences of observers, past and present, instead of to the problems and subdivisions of the astronomical discipline.