Firstdark: Milky Way & Aurora

You already know roughly when the core is up. The question that actually costs you something is whether tonight is worth the drive. Firstdark answers that one. It works out when the sky is genuinely dark where you are standing — not sunset, not civil twilight, the real astronomical dark — then checks the moon against it, and the cloud across those exact hours, and tells you in a sentence. "Go. The sky says yes." Then it tells you which nights this month are the good ones, so you can plan a trip around the moon instead of guessing. AND WHEN THE AURORA IS OUT Kp 5 is a great night in Minnesota and nothing at all in Texas. The number means nothing until you know what your own latitude needs — and that depends on geomagnetic latitude, not the one on the map. Firstdark computes your threshold from your coordinates every time, and never reads it off a table of cities. If aurora cannot reach…