2017年IAO理论高年组第4题-美国日食

	需要解答 本题目目前没有解答。要不要你来试试！

低年组对应问题：2017年IAO理论低年组第4题-美国日食

英文题目

β-4. Eclipse in USA. A little more than two months ago, on August 21, 2017 from West to East of the USA territory a total solar eclipse was observed. The middle line of the track of the eclipse is shown schematically on the map. Below are four pictures taken by the Bulgarian-Russian group of observers who were near the West coast, in the state Oregon, through which the Moon’s shadow ran almost along the latitude φ=45°. The local time (UT-07) Of the shots is indicated below each image. At the moment of totality the Sun was in the South-Eastern part Of the sky, in χ=59,5° from the South in azimuth, at an altitude of h = 41.9°above the horizon. By using the data and making calculations, estimate:

4.1. the speed of the Moon’s shadow in the state Oregon;

4.2. the width of the path of the total eclipse (in km) on its territory.

IAO2017Tβ-4

中文题目

β-4 美国的日食

两个多月前，即2017年8月21日，在美国西部到东部一带，观测到日全食。日食轨道的中间线已标注在地图上。以下是保加利亚-俄罗斯观察员小组在俄勒冈州西海岸附近拍摄的四张照片，月球的影子几乎沿着纬度φ=45°线行进。拍摄的当地时间（UT-07h）在每张图像下方显示。在食甚时，太阳位于天空的东南部，方位角与正南距离χ=59.5°，高度角h=41.9°。 通过使用数据并进行计算，估算：

4.1.俄勒冈州月球影子的速度;

4.2.日全食月影行进（以千米为单位）的路径宽度。