var options = {
                    projection: new OpenLayers.Projection("EPSG:900913"),
                    displayProjection: new OpenLayers.Projection("EPSG:900913"),
                    units: "m",
                    maxResolution: 156543.0339,
                    maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34,20037508.34, 20037508.34)
                };
     map = new OpenLayers.Map('map1',options);
var gphyLayer = new OpenLayers.Layer.Google("Google Physical",{type:google.maps.MapTypeId.TERRAIN,isBaseLayer:true,sphericalMercator:true });

 wms = new OpenLayers.Layer.WMS("Rasdaman",wmsURL,
            {layers: 'rasdamanImage',
            format:'image/png',
            time:dateText,
            strategies: [new OpenLayers.Strategy.Fixed()],
            transparent: true},{isBaseLayer:false,singleTile: true,ratio: 1});