function calcAzEl(output, T, localtime, latitude, longitude, zone)
{
  var eqTime = calcEquationOfTime(T)
  var theta  = calcSunDeclination(T)
  if (output) {
    document.getElementById("eqtbox").value = Math.floor(eqTime*100 +0.5)/100.0
    document.getElementById("sdbox").value = Math.floor(theta*100+0.5)/100.0
  }
  var solarTimeFix = eqTime + 4.0 * longitude - 60.0 * zone
  var earthRadVec = calcSunRadVector(T)
  var trueSolarTime = localtime + solarTimeFix
  while (trueSolarTime > 1440)
  {
    trueSolarTime -= 1440
  }
  var hourAngle = trueSolarTime / 4.0 - 180.0;
  if (hourAngle < -180)
  {
    hourAngle += 360.0
  }
  var haRad = degToRad(hourAngle)
  var csz = Math.sin(degToRad(latitude)) * Math.sin(degToRad(theta)) + Math.cos(degToRad(latitude)) * Math.cos(degToRad(theta)) * Math.cos(haRad)
  if (csz > 1.0)
  {
    csz = 1.0
  } else if (csz < -1.0)
  {
    csz = -1.0
  }
  var zenith = radToDeg(Math.acos(csz))
  var azDenom = ( Math.cos(degToRad(latitude)) * Math.sin(degToRad(zenith)) )
  if (Math.abs(azDenom) > 0.001) {
    azRad = (( Math.sin(degToRad(latitude)) * Math.cos(degToRad(zenith)) ) - Math.sin(degToRad(theta))) / azDenom
    if (Math.abs(azRad) > 1.0) {
      if (azRad < 0) {
	azRad = -1.0
      } else {
	azRad = 1.0
      }
    }
    var azimuth = 180.0 - radToDeg(Math.acos(azRad))
    if (hourAngle > 0.0) {
      azimuth = -azimuth
    }
  } else {
    if (latitude > 0.0) {
      azimuth = 180.0
    } else {
      azimuth = 0.0
    }
  }
  if (azimuth < 0.0) {
    azimuth += 360.0
  }
  var exoatmElevation = 90.0 - zenith

// Atmospheric Refraction correction

  if (exoatmElevation > 85.0) {
    var refractionCorrection = 0.0;
  } else {
    var te = Math.tan (degToRad(exoatmElevation));
    if (exoatmElevation > 5.0) {
      var refractionCorrection = 58.1 / te - 0.07 / (te*te*te) + 0.000086 / (te*te*te*te*te);
    } else if (exoatmElevation > -0.575) {
      var refractionCorrection = 1735.0 + exoatmElevation * (-518.2 + exoatmElevation * (103.4 + exoatmElevation * (-12.79 + exoatmElevation * 0.711) ) );
    } else {
      var refractionCorrection = -20.774 / te;
    }
    refractionCorrection = refractionCorrection / 3600.0;
  }

  var solarZen = zenith - refractionCorrection;

  if ((output) && (solarZen > 108.0) ) {
    document.getElementById("azbox").value = "dark"
    document.getElementById("elbox").value = "dark"
  } else if (output) {
    document.getElementById("azbox").value = Math.floor(azimuth*100 +0.5)/100.0
    document.getElementById("elbox").value = Math.floor((90.0-solarZen)*100+0.5)/100.0
    if (document.getElementById("showae").checked) {
      showLineGeodesic2("azimuth", "#ffff00", azimuth)
    }
  }
  return (azimuth)
}