Re: Dipping a Light
Useful, especially when you are looking for a distant light, even the markers on bridge towers, and someone says "I see it. No, wait, I don't. No, I do. Wait, I don't."
Now you know they've dipped the light and a quick look-up gives you the range. Or you can put a pencil line on the chart with your compass, i.e. where you expect to dip the light, and when that happens you know "We are here. Ish."