Caeli Deus sanctissime

Here is another hymn for Vespers. I am not totally satisfied with the translation of the first verse. But I am stuck.

Caeli Deus sanctissime, qui lucidum centrum poli candore pingis igneo augens decori lumine.	Most holy God of heaven high, Who made the circle of the sky: You paint it now with burning light, To make it greater and more bright;
Quarto die qui flammeam solis rotam constituens, lunae ministras ordini, vagos recursus siderum,	Who, on the fourth day, set aflame The sun’s great wheel, and rule the same,  The phases of the moon you guide, And stars that wander far and wide,
Ut noctibus, vel lumini diremptionis terminum, primordiis et mensium signum dares notissimum:	To give both night and day a line Dividing dark from light: a sign Most evident to sight and sense, To mark the months as they commence.
Illumina cor hominum, absterge sordes mentium, resolve culpae vinculum, everte moles criminum.	Illuminate the hearts of men, Their unclean minds make pure again. Untie the chains of guilt within, Cast down the heaped-up hills of sin.
Praesta, Pater piissime, Patrique compar Unice, cum Spiritu Paraclito regnans per omne saeculum.	Grant it, dear Father, ever one With Christ our Lord, your only Son, And with the Spirit equally, Ruling for all eternity. Amen.