Another method of presenting the variable star images used to estimate magnitudes, besides the html, flash, or pdf versions, is to use the Stellar Heartbeats Slide Set. This is a powerpoint version of the images. The variable star is located in the center of the image, and it's magnitude and the Julian Day changes with each of the 18 images. This format works best for the entire class to learn the technique together. It has the added advantage that you have control of the pace of the images, and the students do not have the option of looking back at a previous image. (After all, the night sky does not move backwards!) Use the same table and graph provided with the pdf version and the Stellar Heartbeats Slide Set if you elect to use this version of the activity.