Crossword Genius

Person setting up in coalpit, working with earth in the centre? (9)

Ross

I believe the answer is:

ptolemaic

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'person setting' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I don't see?

I don't understand how the remainder of the clue works.

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(Other definitions for ptolemaic that I've seen before include "having old-fashioned ideas about the stars?" , "about astronomical theory" , "Dealing with heavenly bodies" , "such as Cleopatra" .)

I've seen this clue in The Guardian.
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