An Improved, 'Newtonian' Version of the Ebert-Fastie Spectrograph

摘要

A new variation of the off-plane Ebert-Fastie spectrograph is described in which a Newtonian folding arrangement is mounted between the collimator/camera mirror and the grating. This arrangement removes the sagittal and tangential astigmatism and coma of the classical Ebert-Fastie, allowing the design to be extended from a monochromator to CCD spectroscopy. The Newtonian modification (which includes a spherical collimator/camera) results in a point-spread function that is nearly isotropic across the field of view, well suited to spectroscopic studies of stellar objects. This spectrograph is the dedicated science instrument of the Georgia State University 1 m Multiple Telescope Telescope.