function setup_sunchart() {
    var img = document.createElement('img');
    
    img.setAttribute('src', "arrow_up.png");
    img.setAttribute('width', 16);
    img.setAttribute('height', 7);
    img.id = 'sunarr';
    
    var sunchart = document.getElementById('sunchart');
    sunchart.appendChild(img);
    update_sunchart();
}

function update_sunchart() {
    var now = (new Date()).getTime();
    var midn = new Date();
    
    midn.setUTCHours(7); // FIXME: when UTC begins, 4.
    midn.setUTCMinutes(0);
    midn.setUTCSeconds(0);
    
    if(midn.getTime() > now) {
    	midn.setDate(midn.getDate() - 1);
    }
    
    var perc = ((now - midn.getTime()) / 86400000 * 390)-9.5; 


    document.getElementById('sunarr').style.marginLeft = Math.round(perc) + 'px';
    
    setTimeout(update_sunchart, 60000);
}

setup_sunchart();