var lon = 5;

        var lat = 50;

        var zoom = 4;

        var map, layer;



        function init(){



            var options = {

                numZoomLevels: 6,

                controls: []

            };

            map = new OpenLayers.Map( 'olmap', options );



            var urlArray = ["http://maptiles1.earthatlas.info",

                            "http://maptiles2.earthatlas.info",

                            "http://maptiles3.earthatlas.info"];



            naturalearth = new OpenLayers.Layer.TMS( "Natural Earth", urlArray, {layername: 'naturalearth', serviceVersion: '', type:'png'} );

            earthbynight = new OpenLayers.Layer.TMS( "Earth by Night", urlArray, {layername: 'earthbynight', serviceVersion: '', type:'png'} );

            bluemarble = new OpenLayers.Layer.TMS( "Blue Marble", urlArray, {layername: 'bluemarble', serviceVersion: '', type:'png'} );

            map.addLayers([earthbynight, naturalearth, bluemarble]);



            map.addControl(new OpenLayers.Control.LayerSwitcher());

            map.addControl(new OpenLayers.Control.MousePosition());

            map.addControl(new OpenLayers.Control.MouseDefaults());

            map.addControl(new OpenLayers.Control.PanZoomBar());



            map.setCenter(new OpenLayers.LonLat(lon, lat), zoom);

            //map.addControl(new OpenLayers.Control.MousePosition());

        }