Not every editor accepts that this is Sappho's poem. The meter is hagesichorians by the line: x-uu-u--.
δέδυκε μὲν ἀ σελάννα
καὶ Πληΐαδες, μέσαι δὲ
νύκτες, παρὰ δ’ ἔρχετ’ ὤρα,
ἔγω δὲ μόνα κατεύδω. 4
1. δύω, δύσομαι, ἔδυν, δέδυκα enter, of celestial objects, set. ἀ = Ionic ἡ. σελάννα = σελήνη, ἡ moon.
2. Πληΐαδες the constellation The Pleiades. μέσος η ον middle (of).
3. νύξ νυκτός ἡ night. The plural here (meaning the middle of a single night) is a little unusual, but is also seen a few times in Homer. παρ‐έρχομαι pass (by), παρέρχετ’ = παρέρχεται, with tmesis. ὤρα = ὥρα ἡ any time period, time, season.
4. μόνος η ον alone, μόνα = μόνη. κατ‐εύδω = καθ‐εύδω lie down to sleep, sleep; lie still.