Monday, March 16, 2009

Sun tools

Sometime last year I added a Sun and Moon tool to provide information on the sunrise/set and moorise and set and information and links to the sun/moon rise and set azimuth, meaning the compass direction where it will rise or set, barring variations in the local terrain, always an issue in Mt. Rainier NP.

What I don't provide is additional information for the sun during the day, often critical when you want to be in the right spot for lightig, to locate it in the scene, as a backdrop, to know where shade or shadows will be, or simply to know. There are lots of reason. For that I'm a lot more flexible and give the scene more latitude. If it's not perfect, that's ok with me, I'll take what it gives.

But for some it's critical. And to that end there is an interesting Webpage provided by the University of Oregon Solar Radiation Monitoring Labatory with a set of tools for different calculation about the sun and solar radiation. Despite some short comings, it's useful for a number of reasons.

It's advantage is that it can calculate the sun's position for a single day and provide additional information by hour. You have to tinkeri with the variables, but it can determine some important information. I was able to determine that the spring equinox for me will be 3-4 am March 20th. Like I'm going to see that.

It's short comings though need to be remembered. First, it doesn't correct for daylight savings time in the calculation. You have ot remember that or use a different time offset. Second, it's graphical, which isn't bad for someone like me, but if you want tabular data, it doesn't provide that. This leaves some latitude reading the graphs for accurate time.

Otherwise, it's kinda' neat, and certainly useful. I urge you to test drive it for your photography.

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