Keppler’s Laws
All planets move in elliptical orbits, with the sun at one foci
An imaginary line joining a planet and the sun sweeps out an equal area of space in equal amounts of time.
Shape of Earth
Oblate spheroid, 1:298 compression ratio
Capricorn
23.5S
Cancer
23.5 north
Arctic Circle
66.5N
Antarctic Circle
66.5S
Angle of Inclination of the Earth
23.5
Aphelion
Furthest away, slowest speed - July
Perihelion
Closest, fastest speed - January
Greatest time difference occurs
Between the two equinoxes
Sunrise
Upper Limb of Sun breaks the horizon
Sunset
Upper Limb drops below the horizon
Dusk
Centre of the sun 6 degrees below the horizon
Direct Mercator
conformal
Lamberts Conformal
scale is considered to be correct across the chart
Polar Stereographic
conformal