whom you must greet likewise, each by his own name: 'Hail, guardians of the axle-pin, holy and mighty youths, who turn, at a single command, the ever-whirling axle of the wheel of heaven,

The image is mechanical, and gloriously so. Heaven is a kýklos, a wheel; it turns on an áxōn, an axle; and the axle rides on a knṓdax, the little pivot-pin that lets a heavy wheel spin true. These seven gods are the knōdakophýlakes, the keepers of that pin — cosmic mechanics, the maintenance crew of the sky. The universe of this prayer is an engine, and someone has to mind the bearings. What they do, they do hypò hén kéleusma — 'at a single command,' in perfect unison. The word kéleusma is the boatswain's cry that keeps a galley's oars beating together; the whole turning heaven is rowed like a warship, and these 'mighty youths' pull as one. Álkimos is Homer's word for a brave man in battle, so there is something martial in them too — a young, strong, disciplined crew hauling the entire firmament round on its pin, night after night, on command. The sublime here is not vague vastness; it is engineering, manned.