Placement of a scatter cone at the center of the secondary of a Cassegrain telescope greatly reduces Narcissus reflection. To calculate the remaining Narcissus reflection, a time-consuming physical optics code such as GRASP8 is often used to model the effects of reflection and diffraction. Fortunately, the Cassegrain geometry is sufficiently simple that a combination of theoretical analysis and Fourier propagation can yield rapid, accurate results at submillimeter wavelengths. We compare these results with those from GRASP8 for the heterodyne instrument for the far-infrared on the Herschel Space Observatory and confirm the effectiveness of the chosen scatter cone design.
© 2005 Optical Society of America
Robert L. Lucke, Jacqueline Fischer, Arturo M. Polegre, and Douwe A. Beintema, "Fast computation of the Narcissus reflection coefficient for the Herschel far-infrared/submillimeter-wave Cassegrain telescope," Appl. Opt. 44, 5947-5955 (2005)