var imageFiles_q4_13 = new Array();
imageFiles_q4_13['0'] = new Array ('_images/q4_Telescopes.gif', '_images/q4_TelescopesMouseover.gif');

function image_on_q4_13 (position) {
   var doc = eval("document.imageq4_13" + position);
   doc.src = imageFiles_q4_13[position][1];
}

function image_off_q4_13 (position) {
   var doc = eval("document.imageq4_13" + position);
   doc.src = imageFiles_q4_13[position][0];
}