(sandy Hook, CT)Butterfly or green moth?
Yes, you have a male luna moth. The male moths have large feathery antenna while female antenna are narrow and feathery. These large antenna on the males allows them to find the females by sensing the phermones given off by the female.
Beautiful moths. This insect overwinters as a pupa and then the moths emerge in April or May to lay eggs. Larva feed on a variety of plants including walnut, hickory, birch, sweet gum, sumac, alder and persimmon.