Hot answers tagged


Around sunrise and sunset, the sun is much less intense. You would get around 5 times less intensity in the first or last hour of sunlight than in the middle of the day. Here is a graph of this effect (It's from a paper, though the paper itself is behind a paywall), and another one which also shows the effect of latitude. Therefore, while you can’t say ...


This web page should do the job, and also has a draggable map and list of cities if you want to select one of those rather than entering in manual co-ordinates.


If you're old-school, here is a device I just learned about today (and it should fit into your pack): The Sunsetwheel. It's a sliderule type device, and may take a few minutes to learn how to use it, but it can give you data without having a smart phone on you at all times.

Only top voted, non community-wiki answers of a minimum length are eligible