Please forgive my asking about the Azimuth and Zenith Angle parameters for FLAASH, as I know it has been covered here many time before. I have a specific question about RapidEye 1B. Based upon the parameters that are listed in my accompanying metadata record, it would seem intuitive that I could calculate the Zenith Angle using the "spaceCraftViewAngle" which has a reasonable value of 3.067680e+00 degrees. Therefore I believe the FLAASH Zenith Angle parameter would equal 180 - |3.067680| = 176.9322 degrees. RapidEye's product information states that the "azimuthAngle" is "the angle from true north at the image or tile center to the scan (line) direction at image center in clockwise positive degrees". My metadata shows the "azimuthAngle" as 2.801200e+02 degrees. Since FLAASH expects values between 180 and -180, would it be correct to assume that I could subtract 280.12 degrees from 360 to arrive at 79.88 degrees, but this would be on the negative side of the semi-circle, so it would actually be -79.88 degrees. For the Azimuth Angle, FLAASH wants the perspective from the ground looking towards the sensor, which would be the opposite of 79.88, and the parameter for entry would be 180 - 79.88 = 100.12. Thanks for any assistance someone may provide!!