Scientists rent rooms as required (11)

I believe the answer is:

astronomers

I'm a little stuck... Click here to teach me more about this clue!

'scientists' is the definition.
(astronomer is a kind of scientist)

'rent rooms as required' is the wordplay.
'rent rooms as' can be anagrammed to 'ASTRONOMERS'.
But, I am unsure how the anagram is indicated.

Can you help me to learn more?

(Other definitions for astronomers that I've seen before include "Monster oars (anag.)" , "Moon-starers (anag)" .)

I've seen this clue in The Globe and Mail.

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