| Description | This is a classic astro-imaging target: it's large, dramatic, and quick to image with the right filter. Caldwell divides it into two parts: the nebula and the central cluster. However, discovery was more complicated, with 5 separate NGC catalog entries, literally the brightest features within the overall nebula. It's a case of the Herschel's not seeing the forest for the trees (er... nebula for the bright spots). We can infer it's a challenging visual target, certainly without filters. I've listed it as NGC 2537, which is common because it was the first in the list, and by convention has come to mean the whole target. William Herschel cataloged the cluster (see C50) and noted some nebulosity in 1784. Then his son, John, in 1830 cataloged NGC 2239. Albert Marth (1864) discovered NGC 2238, another part of the nebula. Lewis Swift (1871, 1885) identified the main nebulous patch, NGC 2237, and NGC 2246.
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