Timer Update not following new location

I have a timer that updates the map and is working very well, except for the issue that the moving point eventually disappears off the map, so the map is not centering on the new location.

Thanks

Further to the above, forgot to mention that I can have any number of moving points and would like the map to keep them all in view. When the map loads I call the javascript maploaded as per a previous forum entry,

 <Simplovation:Map runat="server" ID="Map1" OnClientMapLoaded="mapLoaded" />
<script type="text/javascript">
// This method is run once the map has completed loading on the page
function mapLoaded()
{
    var map = $find("<%=Map1.ClientID%>");
    //This code will center the map on all the shapes that are plotted
    var locations = new Array();
    for(var a = 0; a < map.get_Map().GetShapeLayerCount(); a++)
    {
        for(var b = 0; b < map.get_Map().GetShapeLayerByIndex(a).GetShapeCount(); b++)
        {
            Array.addRange(locations, map.get_Map().GetShapeLayerByIndex(a).GetShapeByIndex(b).GetPoints());
        }
    }
    if (locations.length != 0)
        map.get_Map().SetMapView(locations);
}
</script>

but it doesn't appear to fire after timer fires the updatemap() sub

Do you have any suggestions as to how best to set a boundary to display all points after a update.