Erik Hofman wrote: > Since you are already familiar with this stuff, I need the function to > calculate the sun position (in degrees or radians) above the horizon > at a certain time/lat/lon. What is this normally called: > RightAscension, Declination, Magnitude or something else?
None of the above. :) Right ascention and declination are the longitude and latitude of the celestial coordinate system. They specify directions to things that are outside our solar system. Things inside it will appear to move depending on their relative position with the earth. Magnitude refers to the brightness of a star. The sun position can be computed if you know the orbital parameters for the earth, but the details are tricky. The way it would work is to define some "sol-centric" coordinate system in which the earth moves, compute a line from the earthbound eyepoint to the sun, figure out what orientation the earth will be in at that moment, and then do an euler angle decomposition relative to the WGS-84 "up" vector and the earth's axis. Basically, it's not easy, which is why it's probably quickest to ask the author to change the license. :) Andy _______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
