ياO أيُّهاyou (vocative) القَمرُthe moon الذيwhich بِمَغيبهat its setting
يا أيُّها القَمرُ الذي بِمَغيبه
صبغتwere dyed ثيابُthe robes الليلِof night فَهيso they are حدادُmourning garb
صبغت ثيابُ الليلِ فَهي حدادُ
O moon, at whose setting
O moon that when it sets
the robes of night were dyed, and so they are mourning garb.
The garments of the night are dyed in mourning
Sol 6.1