"Canopy of Heaven" is a beautiful phrase that describes the sky above us. Synonyms for this phrase could include "firmament," "celestial dome," or simply "heavens." Other synonyms might include "vault of heaven," "azure canopy," or "ethereal sphere." The phrase "dome of the sky" is also fitting, as it implies the expansive and all-encompassing nature of the heavens above. In more poetic language, one could refer to the "eternal blue," "infinite sky," or "cosmic expanse." Whatever words we choose to describe the beauty and wonder of the sky, we can all appreciate the limitless expanse of the world above us.