- Lake Shannon (Wikipedia)
Lake Shannon is a long, narrow reservoir on the Baker River in Skagit County, Washington in the United States. Formed in the 1920s by the construction of an arch dam just above the town of Concrete, the lake is approximately 7.5 miles (12 km) long and averages 0.6 miles (1 km) wide when full. Located just outside the western boundary of North Cascades National Park, Lake Shannon serves as the lower reservoir for Puget Sound Energy’s Baker River Hydroelectric Project.
- Absolute magnitude (Wikipedia)
In astronomy, absolute magnitude (M) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object’s absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly 10 parsecs (32.6 light-years), without extinction (or dimming) of its light due to absorption by interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. For Solar System bodies that shine in reflected light, a different definition of absolute magnitude (H) is used, based on a standard reference distance of one astronomical unit.