Fig. 3.

Chart of the sky close to λ Sgr generated as it appeared to a Chinese observer in the May 48 BCE. The grey arrow points to the approximate location of the ancient observation. The globular cluster NGC 6656 (M 22) is located about 2.5° north-west of this location (about 2.3° north-east of λ Sgr). This chart was generated using XEphem (version 3.7.3, Downey 2011).
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