19 of 19 people found the following review helpful
New Illuminator in 2009,
This review is from: Celestron 44104 500x Power Advanced Biological Microscope (Electronics)
The Celestron web site says that beginning in Jan 2009 the illuminator was upgraded to an LED system which is cool to the touch. I have not seen it, but it does address the heat concerns as LED's run at room temperature. I suppose that older inventory has the overheating issue. Be sure to check prior to purchasing.