7 Was mounted high in top of heaven sheen,

sheen > shining, resplendent; beautiful (applicable both to "Hesperus" and "heauen")

8 And warned his other brethren joyous

brethren joyous > heavenly brothers

9 To light their blessed lamps in Jove's eternal house.

304.52

All suddenly dim woxe the dampish ayre,
2 And griesly shadowes couered heauen bright,
That now with thousand starres was decked fayre;
4 Which when the Prince beheld, a lothfull sight,
And that perforce, for want of lenger light,
6 He mote surcease his suit, and lose the hope
Of his long labour, he gan fowly wyte
8 His wicked fortune, that had turnd aslope,
And cursed night, that reft from him so goodly scope.

1 All suddenly dim waxed the dampish air,

waxed > grew, became

2 And grisly shadows covered heaven bright,