Formality given to paintings, etc. - a heavenly plan (4,5)

I believe the answer is:

star chart

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'a heavenly plan' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.

'formality given to paintings etc' is the wordplay.
'formality' becomes 'starch' (being excessively formal or stiff).
'given to' is a charade indicator (letters next to each other).
'paintings etc' becomes 'art' (works of art).
'starch'+'art'='STAR CHART'

Can you help me to learn more?

(Another definition for star chart that I've seen is " Old marine guide".)

I've seen this clue in the Sydney Morning Herald.

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