... Observing may be done from any location. ... See this link for further details, limiting magnitude charts, and star count tables: http://www.imo.net/visual/major/observation/lm Proof Point Information : Shapley-Sawyer Classification: Reference: http://x.astrogeek.org/articles/article.php?article_id=15 Brief Description: I - High concentration toward the center; E.g ., NGC 6864, M75 II - Dense central condensation; E.g ., NGC 7089, M2 III - Strong inner core of stars ; E.g ., ...