Which object is cited as potentially the first *new* non-stellar object formally recorded by a systematic observer like Messier?

Answer

M27, the Dumbbell Nebula

M27, the Dumbbell Nebula, observed by Messier in 1764, is considered a primary candidate for the first *new* permanent deep-sky object logged by a systematic observer attempting to distinguish these objects from comets.

Which object is cited as potentially the first *new* non-stellar object formally recorded by a systematic observer like Messier?
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