2017年IOAA理论第12题-海难

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IOAA赛场上通常是使用英文回答问题，所以建议各位用英文回答本题

英文原题

(T12) Shipwreck [40 marks],,,

You are shipwrecked on an island. Fortunately, you are still wearing a watch that is set to Bangkok time, and you also have a compass, an atlas and a calculator. You are initially unconscious, but wake up to find it has recently become dark. Unfortunately, it is cloudy. An hour or so later you see Orion through a gap in the clouds. You estimate that the star “Rigel” is about 52.5º above the horizon and with your compass you find that it has an astronomical azimuth of 109º. Your watch says it is currently 01:00 on the 21^st November 2017. You happen to remember from your astronomy class that Greenwich Sidereal Time (GST) at 00h UT 1^st January 2017 is about 6h 43min and that the R.A. and Dec of Rigel are 5h 15min and -8°11′, respectively. Bangkok is in the UT+7 time zone.

a) Find the Local Hour Angle (LHA) of Rigel. [10]

b) Find the current Greenwich sidereal time (GST). [10]

c) Find the longitude of the island. [5]

d) Find, to the nearest arcminute, the Latitude of the island. [15]

中文翻译

海难

遇到海难之后你来到了一个岛上。幸运的是你带着手表，它显示着曼谷时区的时间。你还有一个指南针，一个星图以及一个计算器。你失去了意识，醒来后发现天已经黑了。不幸的是天空中阴云密布。一小时或更久之后你在云缝中看到了猎户座。你估计出了参宿七的地平高度为52.5.°，利用指南针你测量出了它的方位角为109°，这是从北点起算。这时手表显示的时间为2017年11月21日01:00.并且你从天文课上学到了世界时2017年1月1日0时，格林尼治地方恒星时（GST）约为6h43min。参宿七的赤经RA为5h15min，赤纬Dec为-8°11′，曼谷时区为UT+7。

（a）计算观测时参宿七的时角（LHA）。

（b）计算观测时的格林尼治地方恒星时（GST）。

（c）计算这个岛的地理经度。

（d）计算这个岛的地理纬度，精确到分。