Nebular fabry-perot, pepsios, and sisam monochromators

The usefulness of the Fabry-Perot and Pepsios monochromators when studying visible nebular lines is pointed out. A method of scanning and modulating a Sisam monochromator in the visible is described. The potential performances in a variety of idealized noise conditions of Fabry-Perot, Pepsois, Sisam, and Sisam x Fabry-Perot monochromators for nebular studies are then analyzed.