Golimowski D A, Clampin M, Durrance S T, Barkhouser R H
Appl Opt. 1992 Aug 1;31(22):4405-16. doi: 10.1364/AO.31.004405.
The first results of a new approach to ground-based stellar coronagraphy are reported. A coronagraph has been equipped with an image-motion compensation system for the stabilization of the telescope field, permitting both improved image resolution and contrast at optical wavelengths. By stopping the telescope aperture D to ~ 4 r(0), where r(0) is Fried's parameter, the maximum attainable resolution gain factor of 2.2 was achieved. Gains measured for D/r(0) > 14 were below the theoretical value of 1.3 theory and were indicative of centroid anisoplanatism, a small spatial coherence outer scale, or both. These effects are also evidenced by diminished power at low frequencies in the power spectrum of image motion over the full telescope aperture. A comparison of stabilized and unstabilized images shows that this coronagraph may detect circumstellar objects 2 magnitudes fainter than those detectable with a conventional coronagraph.
报道了一种新型地基恒星日冕仪方法的首批结果。一台日冕仪配备了图像运动补偿系统，用于稳定望远镜视场，从而在光学波长下既能提高图像分辨率又能提高对比度。通过将望远镜孔径D缩小到约4r(0)（其中r(0)是弗里德参数），实现了2.2的最大可达到的分辨率增益因子。对于D/r(0) > 14测量得到的增益低于理论值1.3，这表明存在质心非等晕性、较小的空间相干外尺度，或两者皆有。这些效应在整个望远镜孔径上图像运动功率谱的低频功率降低中也得到了证明。稳定图像和未稳定图像的比较表明，这种日冕仪可以探测到比传统日冕仪可探测到的恒星周围天体暗2个星等的天体。
