Poetry: Is this poem just one long stanza?

[welshhighschool2005]

So, I am doing a presentation about poetry in my class today and I was wondering if the following poem is just one long stanza or if there is another word for it:

WHEN I heard the learn’d astronomer;
When the proofs, the figures, were ranged in columns before me;
When I was shown the charts and the diagrams, to add, divide, and measure them;
When I, sitting, heard the astronomer, where he lectured with much applause in the lecture-room,
How soon, unaccountable, I became tired and sick; 5
Till rising and gliding out, I wander’d off by myself,
In the mystical moist night-air, and from time to time,
Look’d up in perfect silence at the stars.