Procedure : 1. Look at the pictures in Fig 2 & 3. How would you find the comet ? Here is one suggestion - take transparent paper and put it on top of Figure 2; mark the brightest stars ; move the transparent paper on top of Figure 3; and line up the positions of the stars your just marked . Find the one object that does not match . Circle that object ie., the comet . If you did this exercise on a computer ,you would also superimpose the pictures ,and find the comet by "blinking " both pictures . Whenever astronomers go observing , we take a "finding chart " along . This is a sketch (or previously taken photo ) of the general region that we wish to observe . At the observatory we then compare the patterns on the sketch to the pattern seen through the telescope . Let's do the same Compare the patterns of Figures 1 & 2. Identify the stars "Omicron Draconis " and "SAO 029766 ", and circle them on the transparent paper . Figure out how much the comet has moved in the two hour between Figures 2 & 3. Take a ruler and measure the distance between the comet images in the two photographs (on the transparent paper ). This is mm