Everybody loves eclipses. Grand alignments caused by the application of gravity to planetary bodies and the luck of being in just the right place, at the right time. On August 21st, 2017 the US will experience a total solar eclipse spanning the country from the Pacific to the Atlantic Ocean. This hasn't occurred since June 8, 1918.
As I read about the upcoming stellar wonder, I saw that the city of Casper, Wyoming will be directly along the path of totality. That's a ways to travel and I wondered if STK could tell me how much of the eclipse I'd be able to see from my hometown of Colorado Springs, Colorado. Many references show the path of totality, but few show how much sunlight will be blocked along that path, where the eclipse is not total.
Using STK's Volumetrics tool, we were able to easily generate a partial eclipse path that shows where the Sun is at least 90% eclipsed by the Moon. In the graphic below there are two Volumetrics. The first appears as a circle sweeping across the US, where the blue center shows a 0% solar intensity, which is the complement to percent eclipse. Meaning the 10% solar intensity along the edge of the Volumetric is the same as 90% of the Sun being blocked by the Moon. The second Volumetric trails behind the first Volumetric displaying how long the 90% (or greater) eclipse will last.
Colorado Springs is just outside the red outer edge of the 90% eclipse path. From my view as the Moon passes overhead it will reach a point where it blocks almost 90% of the Sun, which means I would still need eye protection! If I traveled to the darker blue areas, I would able to see a greater level of eclipse and at least a 90% eclipse for over 17 minutes!