From Event: SPIE Optical Engineering + Applications, 2017
Obstructions due to large secondary mirrors, primary mirror segmentation, and secondary mirror support struts all introduce diffraction artifacts that limit the performance offered by coronagraphs. However, just as vortex coronagraphs provides theoretically ideal cancellation of on-axis starlight for clear apertures, the Polynomial Apodized Vortex Coronagraph (PAVC) completely blocks on-axis light for apertures with central obscurations, and delivers off-axis throughput that improves as the topological charge of the vortex increases. We examine the sensitivity of PAVC designs to tip/tilt aberrations and stellar angular size, and discuss methods for mitigating these effects. By imposing additional constraints on the pupil plane apodization, we decrease the sensitivity of the PAVC to the small positional shifts of the on-axis source induced by either tip/tilt or stellar angular size; providing a route to overcoming an important hurdle facing the performance of vortex coronagraphs on telescopes with complicated pupils.
Kevin Fogarty, Laurent Pueyo, Johan Mazoyer, and Mamadou N'Diaye, "Tip/tilt optimizations for polynomial apodized vortex coronagraphs on obscured telescope pupils," Proc. SPIE 10400, Techniques and Instrumentation for Detection of Exoplanets VIII, 104000T (Presented at SPIE Optical Engineering + Applications: August 09, 2017; Published: 12 September 2017); https://doi.org/10.1117/12.2274603.
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