What was the primary motivation for astronomers like Halley and Cheseaux cataloging nebulae in the early 18th century?

Answer

To rule them out as potential comets

Comet seeking was a high priority; astronomers cataloged these faint, fuzzy patches to document them only so they could be excluded from lists of moving comets.

What was the primary motivation for astronomers like Halley and Cheseaux cataloging nebulae in the early 18th century?
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