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We present early laboratory simulations and extensive on-sky tests validatingof the performance of a shaped pupil coronagraph (SPC) behind an extreme-AOcorrected beam of the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO)system. In tests with the SCExAO internal source/wavefront error simulator, thenormalized intensity profile for the SPC degrades more slowly than for the Lyotcoronagraph as low-order aberrations reduce the Strehl ratio from extremelyhigh values (S.R. $\sim$ 0.93--0.99) to those characteristic of currentground-based extreme AO systems (S.R. $\sim$ 0.74--0.93) and then slightlylower values down to S.R. $\sim$ 0.57. On-sky SCExAO data taken with the SPCand other coronagraphs for brown dwarf/planet-hosting stars HD 1160 and HR 8799provide further evidence for the SPC's robustness to low-order aberrations.From H-band Strehl ratios of 80% to 70%, the Lyot coronagraph's performance vs.that of the SPC may degrade even faster on sky than is seen in our internalsource simulations. The 5-$\sigma$ contrast also degrades faster (by a factorof two) for the Lyot than the SPC. The SPC we use was designed as a technologydemonstrator only, with a contrast floor, throughput, and outer working anglepoorly matched for SCExAO's current AO performance and poorly tuned for imagingthe HR 8799 planets. Nevertheless, we detect HR 8799 cde with SCExAO/CHARISusing the SPC in broadband mode, where the S/N for planet e is within 30% ofthat obtained using the vortex coronagraph. The shaped-pupil coronagraph is apromising design demonstrated to be robust in the presence of low-orderaberrations and may be well-suited for future ground and space-based directimaging observations, especially those focused on follow-up exoplanetcharacterization and technology demonstration of deep contrast withinwell-defined regions of the image plane.

Laboratory and On-Sky Validation of the Shaped Pupil Coronagraph's Sensitivity to Low-Order Aberrations With Active Wavefront Control