If, when hearing that I have been stilled at last, they stand at the door, Watching the full-starred heavens that winter sees,
Another stanza opening with that hypothetical "if" construction!
Now the speaker imagines that his friends and neighbors will hear about his death while standing in an open doorway, looking up at the night sky. (Except that it's a "winter" sky – they probably shouldn't be standing with the door open.)
Will this thought rise on those who will meet my face no more, "He was one who had an eye for such mysteries"?
The speaker wonders whether the night sky will inspire his friends to remember him as someone who loved stargazing.
This stanza, like stanzas 1 and 5, is constructed as a question.