Beckers Effect in a Fabry-Pérot Imaging Interferometer and Its Effects on Magnetic Field Measurements
Abstract
The Beckers effect and its impact on the optical performance of a triple-etalon Fabry-Pérot imaging spectral interferometer, such as that intended for use in the Advanced Technology Solar Telescope visible tunable filter, are analyzed in terms of its impacts on line profiles and spatial resolution. In this multi-etalon design, the interferometer is mounted in a telecentric beam. The Beckers effect refers to the pupil apodization in this configuration caused by the dependence of the spectral transmittance of Fabry-Pérot etalons on the angle of incidence of impinging rays. We find that the effect on the imaging and spectral performance can be significant even for the high F-number intermediate images required for narrowband imaging. We go on to explore the impact on Stokes line profiles at 6303Å as well as the cross-talk caused by the degraded point spread function, and analyze the resultant error in the calculated magnetic fields. We gratefully acknowledge the National Science Foundation and the National Solar Observatory for their support of this work.
- Publication:
-
American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22020623R