This stanza consists of four lines that describe the dawn in a very straightforward fashion. It begins with the command "Wake!". Since this is a verb in the imperative mood, we assume that the narrator is addressing one or more people and telling them that it is time to wake up from their slumbers.
The rest of the stanza describes sunrise. As the sun rises, the sky brightens so one can no longer see the stars. The poet describes this as if the Sun were chasing the stars from the skies. Next, the light of the sun is seen as banishing darkness, expressed as "Night."
Finally, a ray of light from the rising sun strikes a tall tower, the "Sultan's turret".
Normally, the "aubade" or morning song is an explicit love song addressed to an individual, but in this case, the poet is attempting a more generic "carpe diem" theme, focused on waking up and seizing the pleasures that the day will offer.