Predicted sunset 17:41, observed sunset 17:41

I watched the sun set from my rooftop today and just had to take a picture. The direction is pretty much due south, and the sun is about to set over the mountain called Løvstakken (“the stack of leaves”, so called due to its shape, I guess).

The top picture shows the horizon as seen from my rooftop just before sunset today. The graph is a zoomed view of the computed horizon at suncurves.com.

The clear weather also enabled me to do some on-the-spot verification of the suncurves.com computations. My colleague Paul and I have made a program that computes the apparent horizon from any location worldwide. This horizon is then combined with data for the sun’s path across the sky. The intersections between the two define the times for sunrise and sunset for any day of the year. Our data is obviously a lot more accurate than the standard sunrise/sunset times that you find elsewhere on the web.

But just how accurate are our calculations? Today our program said that the sun would set at 17:41 (see the table in the picture), and that was spot-on for today. We’ve seen that our times are usually with a 5-minute margin of error. When you accumulate that over a full year, which we do to compute what we call a sun index, the results are very very reliable.

If you’d like, you can find your own sunset and sunrise times for places that you care about. The site is free to use as long as you register. Go on, give it a try in our location finder. Or click here to find a list of our demo pages for sites around the world.

And tell your friends about it if you like it – we think a lot of people out there would think that this is cool.

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Sun returns to Longyearbyen, Svalbard

After a long, dark polar night, the sun finally returned to Longyearbyen, Svalbard today. According to our calculations, the sun had been away since 6 October at the old hospital staircase. Now the hospital is gone, but the stairs have been left standing to mark the spot where the inhabitants celebrate the annual return of the sun.

This is what the sun curve for today looks like for that particular spot:

Click on the picture to see the full sun stats. The picture shows the 360-degree horizon the way we’ve computed it, as well as the sun’s path throughout the day. As you can see, it barely shows over the mountains in two bursts just after noon.

Our unique method allows for such computations for virtually any location worldwide. Just go to our location finder, type an address and let us compute the horizon and the sun curves on the fly. One of the things we do is to compute the accurate sunrise and sunset times for each day of the year. It’s free, and it’s a very useful tool if you’re buying a house or a plot. Thanks in advance for sharing!

Sun Maps for Bergen, Norway

We’ve developed a program that computes the horizon at any location worldwide. This enables us to compute the actual sunrise and sunset times for each day of the year. Here’s a map that shows the local time of sunset in Bergen on 21 June, normally one of the longest day of the year:

The sunset times for 21 June in Bergen, Noway

And here’s the number of hours with sunlight on the same day:

The number of sun hours per day in midsummer