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Andrew E.; et al. Deep Hubble Space Telescope Imaging of Sextans A. II. Cepheids and Distance (PDF). The Astronomical Journal. March 2003, 125: 1261. 引文格式1维护:显式使用等标签
故,因此人馬座A*成像難度也較高,而這樣的技術問題,也使得人馬座A*的相關照片較晚發布。 Reid and Brunthaler 2004 The GRAVITY collaboration. A geometric distance measurement to the Galactic center