Glossary term: 格林尼治标准时区（GMT）
Description: 历史悠久的英国格林威治皇家天文台所在的时区被称为格林威治标准时区，或西欧时区。历史上，格林威治标准时间（GMT）是皇家天文台确定的平均太阳时，并被用作船上携带的海军计时器的参考点。航海家通过使用六分仪或类似装置进行观察来确定当地正午的时间（一天中太阳到达的地平线以上的最高点），并将其与计时器显示的格林威治标准时间进行比较，根据两者的差值确定自己的地理经度。在现代系统中，GMT 时区的时间对应于协调世界时 (UTC)，写为“UTC + 0h”。
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
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