Horváth Gábor, Slíz-Balogh Judit, Pomozi István, Kriska György
Appl Opt. 2021 May 1;60(13):3609-3616. doi: 10.1364/AO.421177.
During the total solar eclipses on 11 August 1999 in Kecel (Hungary) and on 29 March 2006 in Side (Turkey), two Hungarian groups performed full-sky imaging polarimetric measurements of the eclipsed sky. They observed the spatiotemporal change of the celestial polarization pattern and detected three polarization neutral points as well as two points with maximal polarization of the sky. Parallel to these studies, the polarization pattern in front of the lunar disc, the solar corona, and the surrounding sky have also been measured. During the total solar eclipse on 21 August 2017 in the USA (Rexburg-Idaho, Madras-Oregon), three American/international groups have measured the polarization characteristics of the full sky and the solar corona. The first group observed the spatiotemporal variation of the celestial polarization pattern, and the second group detected three polarization neutral points of the sky and observed two neutral points of the solar corona. The latter were named as Minnaert and van de Hulst neutral points. The third group observed two neutral points of the lunar disc. We have reanalyzed the earlier polarization patterns of the lunar disc, solar corona, and the surrounding sky measured during the Hungarian total eclipse on 11 August 1999. In these reanalyzed polarization patterns, all four neutral points observed during the eclipse on 21 August 2017 in the USA occur: the Minnaert/van de Hulst neutral point pair above/below the eclipsed Sun, where coronal polarization is canceled by sky polarization, and the northern and southern (unnamed) neutral points of the lunar disc, where the directions of polarization of coronal light and foreground skylight are perpendicular to each other with the same polarized intensity. We name the latter two polarization neutral points after Coulson and Vorobiev.
1999年8月11日在凯采尔（匈牙利）以及2006年3月29日在锡德（土耳其）发生日全食期间，两个匈牙利团队对日食期间的天空进行了全天空成像偏振测量。他们观测了天体偏振模式的时空变化，检测到了三个偏振中性点以及天空中两个偏振极大点。与这些研究并行，还测量了月球盘面、日冕及其周围天空的偏振模式。2017年8月21日在美国（爱达荷州雷克斯堡、俄勒冈州马德拉斯）发生日全食期间，三个美国/国际团队测量了全天空和日冕的偏振特性。第一组观测了天体偏振模式的时空变化，第二组检测到了天空的三个偏振中性点，并观测到了日冕的两个中性点。后者被命名为明纳尔特和范德胡尔斯中性点。第三组观测到了月球盘面的两个中性点。我们重新分析了1999年8月11日匈牙利日全食期间测量的月球盘面、日冕及其周围天空的早期偏振模式。在这些重新分析的偏振模式中，出现了2017年8月21日美国日食期间观测到的所有四个中性点：日全食太阳上方/下方的明纳尔特/范德胡尔斯中性点对，在那里日冕偏振被天空偏振抵消；以及月球盘面的北部和南部（未命名）中性点，在那里日冕光和前景天光的偏振方向相互垂直且偏振强度相同。我们以后者的名字库森和沃罗比耶夫来命名这两个偏振中性点。
