| Traditional methods of data collection in active fringe tracking Michelson stellar interferometers involve logging and analyzing the signals within the fringe tracking system for the scientific information about the object being observed. While these methods are robust and have produced excellent scientific results, they become more problematic as next-generation Michelson stellar interferometers are built with more telescopes and the aim of performing routine imaging.;The Center for High Angular Resolution Astronomy (CHARA) Array is one such next-generation instrument presently under construction on Mount Wilson, north of Los Angeles, California. The CHARA Array will feature a separation of the tasks of active fringe tracking and imaging, thereby increasing the bandwidth, sensitivity, and data acquisition rate. Presented is a prototype version of an imager for the CHARA Array. The prototype imager employs single-mode fiber optic strands to convey the light from simulated telescopes to a smaller, non-redundant, remapped pupil plane, which in turn feeds a low resolution prism spectrograph. The spectrograph features two cylindrical optical elements whose net effect is to focus the light to a smaller plate scale in the spectral dimension than in the orthogonal spatial dimension. The actual Array imager will build on lessons learned from the prototype and will include capability for five telescopes, further degrees of freedom in adjustment, a computer interface, and automatic intensity calibration. |
