It's great to see a translation from Carmina Gadelica here, thanks very much for providing that.
Carmichael allowed himself rather a lot of freedom in his translations. While there's a decent argument that "na gile" (of the whiteness) means "of the moon", I can't see how "na rinne" (singular) can mean "of the planets" (plural) - it's clearly singular and means either "of the world" or perhaps "of creation" or even "of the universe"). And it seems unreasonable in context to treat "na speura" as "of the sky" instead of "of heaven", and I can't imagine how "lub" becomes "Beam" (or why it is capitalised).
Despite those comments, I wouldn't put up an alternative translation to Carmichael's - he may have had good reason for the things noted above as oddities; after all, my Gaelic is middle and late 20th century, and Carmichael's was 19th century, a lot closer to the origins of these lines than is mine.
Dance of the Druids (aka The Summoning) is a song composed by Bear McCreary on a Gaelic prayer transcribed by Alexander Carmichael in his “Carmina Gadelica” (1900) entitled “Duan na Muthairne” ( Rune of the Muthairn).
An ancient song still known at South Uist in 1874, the witness Duncan MacLellan had heard from an old woman that repeated long chants night after night by the fire.
http://terreceltiche.altervista.org/outlander-dance-of-the-druids/