Vaughan's speaker feels constantly watched and silently judged. The people who doubt them are pictured as constellations: distant, fixed in place, looking down from above. A star can't be argued with or reached, and that is exactly the problem here. These judges read the speaker "like a book" and pick apart their life, yet never say a word.
The second half turns inward. The speaker admits to trying to trust "fake, shaded people" as friends, calling them "half-friends." The poem suggests these people hide their real opinions because they want to keep up a pretense and protect their own secrets. Standing on "pedestals," they act superior while staying safely quiet.
The mood is uneasy and quietly resentful. Repeating "perpetual" and the constellation image at the end makes the judgment feel endless, as if the speaker can never escape being looked at, or ever learn what is really being thought.