As a substitute math teacher for 14 years, I had calculated the amount of time to view the 2017 eclipse anywhere in the path of totality based on the perpendicular distance from the center line. I have on occasion used it in class to challenge pre-calculus/physic students to derive the equation. For this year’s eclipse on April 8, the total eclipse pathway is 124 miles with the center line 62 miles in from both sides. At the center line, the total eclipse can be viewed for approximately 4.5 minutes. I was thinking for this year’s eclipse, if your readers were going to drive several hours or even days to view the eclipse, they would like to know how long they had to view the total eclipse anywhere within the path. Obliviously, the closer to the center line, the longer the viewing time, but it is not a linear relationship. Just a few miles closer to the center line can make considerably greater viewing time of the total eclipse, and justify the half hour more drive (30 miles from the center line will give you 90 percent of possible total eclipse time). To determine how much time to view this unforgettable experience, use the following equation: Time (in minutes to view the total eclipse) = 4.5cos(sin-1 (Y/62)) where Y is the distance in miles from the center line. Or consider using the quick references below:

– 0 miles from center: 4.5 minutes

– 31 miles from center: 3.9 minutes

– 54 miles from center: 2.2 minutes

– 61 miles from center: 0.8 minutes

– 62 miles from center: 0 minutes

William Ellis

Athens, AL