The poem is about the heat and how the person wants it go away because of the damages it causes. Due to the heat "fruit cannot drop," the person wants to "cut apart the heat." The speakers tone is demanding and angry. The speaker desperately want to get rid of the heat. "O wind, rend' open the heat, cut apart the heat, rend it to tatters."
He leaves the astronomer's class to go look at the stars himself, which he found to be a better experience then just listening to someone talk about them.
