M40 was a mistake actually. Messier was looking for a previously reported nebula in the area and only saw this optical double. He marked it as M40 anyways.
My understanding is that all of Messier’s catalogue are ‘mistakes’: he was looking for comets, and making notes of things that weren’t but might be mistaken for comets.
The name of his catalog is: Catalogue of Nebulae and Star Clusters
The Messier catalog was all the things that weren’t the comets that he was looking for. By mistake I meant that M40 isn’t a star cluster or nebula yet Messier added it anyways.
M40 was a mistake actually. Messier was looking for a previously reported nebula in the area and only saw this optical double. He marked it as M40 anyways.
My understanding is that all of Messier’s catalogue are ‘mistakes’: he was looking for comets, and making notes of things that weren’t but might be mistaken for comets.
The name of his catalog is: Catalogue of Nebulae and Star Clusters
The Messier catalog was all the things that weren’t the comets that he was looking for. By mistake I meant that M40 isn’t a star cluster or nebula yet Messier added it anyways.