Variant spelling of astrophel; someone who loves or is devoted to stars.
From Greek 'astro-' (star) and 'phil' (love/lover), this variant appears in literary tradition particularly through Sir Philip Sidney's famous Renaissance sonnet sequence.
The fact that both 'astrophel' and 'astrophil' exist shows how Renaissance writers played with spelling—standardized spelling didn't exist yet, so poets could choose versions that looked or sounded best!
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