The Summer Triangle — 3 stars, 1 seasonal mystery

On clear September evenings, I often find myself looking up just after dusk, expecting the sky to feel a little less like summer. Yet there, still commanding the overhead darkness, are Vega, Altair, and Deneb — the three brilliant stars of the famous Summer Triangle. Their familiar pattern can make the season feel as though it is lingering above us, even as cooler nights and earlier sunsets suggest otherwise. In fact, even as late as mid-November, the Triangle is still nearly overhead soon