//function to read system clock and compute Julian Date
//B. Martin  02/10/2000
// from J.Meeus Astronomical Formulae fro Calculators


function computeJD(JDform) {
	now = new Date()
	var YY = now.getYear()
	var MM = now.getMonth()+1
	var DD = now.getDate()
	var HH = now.getHours()
	var mm = now.getMinutes()
	var ss = now.getSeconds()
	var UToffset = now.getTimezoneOffset()	
       
    with (Math) {  
     		YY = YY+1900
		if(MM<3)
			{
                       
                        YY = YY-1
			MM = MM+12

                        }

		  	
		a = floor(YY/100)
		b = 2 - a + floor(a/4)
		dayFrac = (HH/24+mm/1440+ss/86400)+UToffset/1440
			
		JD = floor(365.25*YY)+floor(30.6001*(MM+1))+DD+dayFrac+1720994.5+b
                
		}

 		       document.JDform.JD.value = JD; 
		setTimeout("computeJD()",1000)

    
}