Seidel sum

Directory

References

Discover

Artist interpretation of space asteroids impacting earth and moon. Meteoroids, meteor impact, end of the world, danger, destruction, dinosaur extinct, Judgement Day, Doomsday Predictions, comet

Major Mass Extinctions

Close up of praying mantis walking on stone ground against a blurred background in Japan

6 Animals That Eat Their Mates

NBA Lakers Celtics Finals Kevin Garnett shooting.

10 Great Sports Rivalries

San Francisco, California/USA-1/18/20: Womens March at Civic Center marching with signs of political protest regarding equality also embracing 2020 presidential candidates and celebrating equality

How Does the U.S. Government Define the Difference Between a Protest and a Riot?

Lake Mead (the impounded Colorado River) at the Hoover Dam. The light-coloured band of rock above the shoreline shows the decrease in water level in the first few years of the 21st century.

6 Lakes That Are Drying Up

Normandy Invasion: Omaha Beach. World War II. D-Day. Infographic. SPOTLIGHT VERSION

Facts and Figures About the Landings on Omaha Beach During the Normandy Invasion on June 6, 1944

An ancient egyptian hieroglyphic painted carving showing the falcon headed god Horus seated on a throne and holding a golden fly whisk. Before him are the Pharoah Seti and the goddess Isis. Interior wall of the temple to Osiris at Abydos, Egypt.

11 Egyptian Gods and Goddesses

Seidel sum

optics

Learn about this topic in these articles:

model for lens aberrations

In optics: Seidel sums
If a lens were perfect and the object were a single point of monochromatic light, then, as noted above, the light wave emerging from the lens would be a portion of a sphere centred about the ideal image point, lying in the paraxial…
Read More