Space coronagraphs are projected to detect exoplanets that are at least 1010 times dimmer than their host stars. Yet, the actual detection threshold depends on the instrument’s wavefront stability and varies by an order of magnitude with the choice of observation strategy and postprocessing method. We consider the performance of the previously introduced observation strategy (dark hole maintenance) and postprocessing algorithm [electric field order reduction (EFOR)] in the presence of various realistic effects. In particular, it will be shown that under some common assumptions, the telescope’s averaged pointing jitter translates into an additional light source incoherent with the residual light from the star (speckles), and that jitter “modes” can be identified in postprocessing and distinguished from a planet signal. We also show that the decrease in contrast due to drift of voltages in deformable mirror actuators can be mitigated by recursive estimation of the electric field in the high-contrast region of the image (dark hole) using electric field conjugation. Moreover, this can be done even when the measured intensity is broadband as long as it is well approximated by an incoherent sum of monochromatic intensities. Finally, we assess the performance of closed-loop versus open-loop observation scenarios through a numerical simulation of the Wide-Field Infra-Red Survey Telescope. In particular, we compare the postprocessing factors of angular differential imaging with and without EFOR, which we extended to account for possible telescope rolls and the presence of pointing jitter. For all observation parameters considered, closed-loop dark hole maintenance resulted in significantly higher postprocessing accuracy.

中文翻译：

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关于指向抖动，执行器漂移，望远镜摇晃和宽带检测器在暗孔维护和电场阶数减少中的影响

预计空间日冕仪将探测出比其宿主恒星暗至少1010倍的系外行星。但是，实际的检测阈值取决于仪器的波阵面稳定性，并随观察策略和后处理方法的选择而变化一个数量级。在各种现实效果的影响下，我们考虑了先前介绍的观察策略（黑洞维护）和后处理算法[电场阶数减少（EFOR）]的性能。特别是，将显示出，在一些常见的假设下，望远镜的平均指向抖动会转换为与恒星的剩余光（斑点）不相干的附加光源，并且抖动“模式”可以在后处理中识别出来，并与行星信号。我们还表明，通过使用电场共轭对图像的高对比度区域（暗孔）中的电场进行递归估计，可以缓解由于可变形镜致动器中的电压漂移而导致的对比度下降。而且，即使被测强度是宽带的，只要单色强度的非相干总和能很好地近似它，就可以做到这一点。最后，我们通过对宽视野红外测量望远镜的数值模拟来评估闭环与开环观测方案的性能。特别是，我们比较了使用和不使用EFOR时角差成像的后处理因素，我们将其扩展为考虑可能的望远镜横摇和指向抖动的存在。对于所有考虑的观测参数，