// This is reverse-engineering of Jim Leonard's picture of MIThenge #5145 use sun.frink use mithengecorridor.frink // Date from EXIF data exifdate = #2007-01-29 16:47:46 Eastern# // According to Lenny Foner, Jim's camera is 2 seconds ahead of GPS time // this was also a 10 s exposure and the date was probably recorded at // the end of exposure (?) truedate = exifdate - 2 s - 5 s // We don't care all that much about refraction, so the temp/pressure figures // below may not be accurate but shouldn't matter much. [sunAzimuth, sunAltitude] = refractedSunAzimuthAltitude[truedate, lat, long, F[29], 30.42 inHg] // Convert Meeus azimuth conventions to normal conventions. sunAzimuth = (sunAzimuth + 180 degrees) mod circle println["True sun azimuth at this time was " + format[sunAzimuth,"degrees",5]] println["Approx. altitude at this time was " + format[sunAltitude,"degrees",5]] // Jim's camera was 39 inches right of the centerline of the fluorescents rightoffset = 39 inches latticewidth = 31.5 in // The grating is offset to the right of the centerline of the corridor? //grateOffset = (8.5 / 43) latticewidth // grateOffset = (8.0 / 45.5) latticewidth grateOffset = (1.5 cm / (11 cm)) latticewidth println["The grate offset is " + format[grateOffset, "inches", 2]] // Distance from grating gratingDist = 460 feet + 7.5 in // Calculate the sun radius at this time. sunRadius = sunRadiusAngle[truedate] println["Sun radius is " + format[sunRadius,"degrees", 5]] azimuthOffset = arctan[rightoffset - grateOffset, gratingDist] println["Azimuth offset is " + format[azimuthOffset,"degrees",5]] corridorAzimuth = sunAzimuth + azimuthOffset println["Corridor azimuth is " + format[corridorAzimuth,"degrees",3]]