As the sky off Menemsha Beach begins to turn pink — the first sign of the show — the beach is already packed. People bring chairs, others set out towels. Everywhere, iPhones are held up and aimed westward. People sipped cups of chowder and slurped oysters.

At around 7:47, the blaze slipped beneath the horizon beyond the sea. The crowd claps. A boat honks, and the parking lot begins to empty. People walk up Basin Road, back to their cars, past a sculpture in the dunes of a man, his harpoon and his catch.