This paper presents a method suitable to readers custom to mark the indices of crystallographical orientation in hexagonal system with coordinates.

提出了适合于读者习惯的应用坐标来标定六方系晶向指数的方法。

youdao

Find this orientation by looking through the crystal at the sky at a time when you can see the sun, mark the sun's direction on the crystal, and your mark will always point towards the sun when you match the beams from even a tiny patch of blue in an otherwise overcast sky.

ECONOMIST: How Norsemen found their way round in cloudy weather