Recent content by irotas

Thanks for the help! Here's the diagram I came up with (following Russ's suggestion): http://public.irotas.fastmail.fm/Solar_elevation.png Any comments/suggestions?

Yeah, I realized that a while ago, but I'd still like to be able to draw a simple picture to help illustrate the point. I might end up having to demonstrate this to higher-ups in my company so I want to make absolutely sure I've got a simple clear picture that they can intuitively understand...

Is there really a simple picture to clarify this observation? I've been scribbling diagrams all day and they all end up terribly complex and totally unenlightening. Any advice on how to draw this out?

I found a solution: http://en.wikipedia.org/wiki/Sunrise_equation#Hour_Angle The correction can by made by modifying how ‘solpos’ computes the cosine of the sunset hour angle. In function ‘ssha()’, simply modify the computation of ‘cssha’ to account for the sine of -50/60 degrees Original...

I have been experimenting with the 'solpos' library from NREL, which is a very nice library for computing solar position (and related) calculations given date/time and coordinates. One thing that surprised me is that the sun's rate-of-change in elevation (angle from the horizon) is not constant...

I am using the following C library for a variety of solar position calculations: http://rredc.nrel.gov/solar/codesandalgorithms/solpos/ In the library, they use the function srss() to compute sunrise and sunset times. Unfortunately, it seems that their equation is for the time that the...