function calcang(form,index)
  //conversions for angles, BCK,Feb 26,2001
{
  var v,m,s;                                  //input:
  if(index==-1) { v=form.storev.value; if(isNaN(v)) return; }
  if(index==0) v=parseFloat(form.g00.value);          // dec deg
  if(index==1) {                                      // deg min sec
    v=parseFloat(form.g01.value); if(isNaN(v)) v=0.0; form.g01.value=eval(v);
    m=parseFloat(form.m01.value); if(isNaN(m)) m=0.0; form.m01.value=eval(m);
    s=parseFloat(form.s01.value); if(isNaN(s)) s=0.0; form.s01.value=eval(s);
    v += m/60. + s/3600.; }
  if(index==2){                                              // deg min
    v=parseFloat(form.g02.value); if(isNaN(v)) v=0.0;
    m=parseFloat(form.m02.value); if(isNaN(m)) m=0.0;
    v += m/60.; }
  if(index==3) v=parseFloat(form.rad.value)*180./Math.PI;    // radian
  if(index==4) v=parseFloat(form.mpi.value)*180.;            // * pi
  if(index==5) v=parseFloat(form.ngr.value)*0.9;             // Neugrad;
  if(index==6) {                                             // sin
    v=parseFloat(form.sin.value);
    if(v>1.0||v<-1.0){warnings(1); return;}
    if(v==1){v=90;}
    else {if(v==-1) {v=-90;}
    else {v=Math.asin(v)*180./Math.PI;}}}
  if(index==7) v=Math.acos(parseFloat(form.cos.value))*180./Math.PI;    // cos
  if(index==8) v=Math.atan(parseFloat(form.tan.value))*180./Math.PI;    // tan
  if(index==9) v=Math.atan(1./parseFloat(form.cot.value))*180./Math.PI; // cot
  if(index==10) v=parseFloat(form.vkr.value)*360.;                      // full circle
  // output:
  st=form.stell.selectedIndex -1; if(st<1) st=1;
  form.storev.value=v;
  form.g00.value=ausga(form,v);                               // dec deg
  var degree = Math.floor(v);                                 // deg min
  var minute = (v-degree)*60.;
  form.g02.value=ausga(form,degree);
  form.m02.value=ausga(form,minute);
  var minu = Math.floor(minute);                           // deg min sec
  form.g01.value=ausga(form,degree);
  form.m01.value=ausga(form,minu);
  form.s01.value=ausga(form,(minute-minu)*60.);
  var rad = v/180.*Math.PI;                     // radian
  form.rad.value=ausga(form,rad);
  form.mpi.value=ausga(form,v/180.);                // * pi
  form.ngr.value=ausga(form,v/0.9);                 // Neugrad
  form.sin.value=ausga(form,Math.sin(rad));         // sin
  form.cos.value=ausga(form,Math.cos(rad));         // cos
  form.tan.value=ausga(form,Math.tan(rad));         // tan
  form.cot.value=ausga(form,1.0/Math.tan(rad));     // cot
  form.vkr.value=ausga(form,v/360.);                // full circle
}