This activity uses a real variable star - W Cyg - in the constellation of Cygnus the swam. The html and flash versions work well; however, the pdf page with the 7 photos of W Cyg and the Finder Slide with the comparison stars do not show up well unless they are downloaded on good quality photographic paper. To help with this difficulty, a powerpoint version of the 7 slides of the close-up of W Cyg has been added to this activity to use in the classroom. Two different powerpoint slide sets have been provided. The Variable Star in Cygnus set is comprised of the 7 slides of W Cyg without the comparison star labeled. You may elect to show your students the unlabeled slide set first. The Variable Star in Cygnus with Comparison Stars set does have the comparison stars labeled. 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 Variable Star in Cygnus with Comparison Stars if you elect to use this version of the activity.
Activity #2: A Variable Star in Cygnus