FIGURE 4-1 The full moon setting over Longs Peak from the summit of Twin Sisters, Rocky Mountain National Park, Colorado. I used the Photographer’s Ephemeris and Sun Surveyor to calculate the best day in 2019 to make this image. Canon EOS 5D Mark IV, Canon Compact-Macro EF 50mm f/2.5, 1/8th, f/8, ISO 100.