Solar System Flashcards
Orbit
Elliptical
Solstices
21st June Summer - longest daylight hours Tropic of Cancer
21st Dec Winter - shortest daylight hours Tropic of Capricorn
23.5 degrees north and south
Earth is how many degrees off vertical axis
23.5
Equinoxes
21st of march and September
Declination
The same as latitude just in astronomers terms
Celestial Sphere
Where all the heavenly bodies are imagined to be projected on to.
Celestial EQ
Projection of earths EQ onto the celestial Sphere
Zenith
The uppermost part of anything
Position of a body directly overhead observer at 90 degrees
Local Hour Angle
Angular measurement from observers celestial meridian to a heavenly body. 0 degrees when overhead
Greenwich Hour Angle
Measured clockwise GHA
240GHA = 120 E
Kepler’s Laws
1 - The orbit of each planet is an ellipse
2 - Radius vector sweeps equal area in equal time
Perihelion
3rd Jan. - Closest to the sun and fastest moving
Aphelion
3rd July - Furthest from the sun slowest moving
Obliquely of Ecliptic
23.5 degrees is the angle between the ecliptic and the celestial EQ
Max Rate of Change of daylight hours
Equinoxes 21st of march and September
Minimum rate of change of daylight hours
Solstices 21st of July and December
Sidereal Year
The time between 2 successive positions of earth, sun, and point in space - 365.6 days
Tropical Year
Time between 2 successive vernal equinoxes (21st march) - relative to the first point of Aries
How are leap years accounted for
Every 400 years, 3 leap years are ignored
Sidereal Day
23hr 56mins Constant
Apparent Solar Day
Time between 2 successive sun points over perpendicular meridian
Mean Solar Day
24 hours constant
Largest difference between apparent sun midday and mean solar day noon
Feb and Nov ~ 15 minutes
