Description: 在一年的時間裡，當地球和地球上的所有天文觀測者繞太陽運行時，這些觀測者的視角會發生變化。與夜空中最遙遠的天體作對比，這種視角變化導致了夜空中較近天體的視位置發生改變。這使得這些天體在一年的時間裡在夜空中看起來移動在微小的橢圓軌跡上，這種效應被稱為週年視差。視運動橢圓的主軸以角度表示，相當於天體（年）視差角的兩倍。視差角相當於觀測者位置變化一個天文單位（AU），即平均地日距離，或相隔半年的天文觀測之間的地球位移的一半。距離單位”parsec“是”秒差距“的縮寫，其定義是，對於距離地球1秒差距的恆星，年視差角相當於1角秒。

Related Terms:

• Parallax

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

This is an automated transliteration of the simplified Chinese translation of this term

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