var fDesc=new Array(); fDesc[0] = "In this lab students use a computer simulation of a telescope equipped with a photon-counting spectrophotometer to take spectra of galaxies. (The equipment is similar to that in the Hubble Redshift-Distance experiment.) They can measure the wavelength of prominent absorption lines determine the redshifts, and store data on disk, import it into spreadsheets, or print it out."; function tShowHide(id, show) { var s = document.getElementById("desc"); if ((s.innerHTML.length<=212 || show==1) && show!=2) { s.innerHTML = fDesc[id]; if (document.getElementById('m1')) document.getElementById('m1').style.display='none'; if (document.getElementById('m2')) document.getElementById('m2').style.display='none'; if (document.getElementById('more_txt')) document.getElementById('more_txt').style.display='inline'; } else { s.innerHTML = ''; } }