Stars and Constellations

Study Notes

Constellations: Imaginary groups of stars forming patterns in the sky.
Stars: Huge celestial bodies, building blocks of galaxies, composed primarily of helium and hydrogen.
Star Cores: Produce light and heat through nuclear reactions.

Size: Determined by the star's distance from Earth.
Brightness:
Apparent Magnitude: Brightness as seen from Earth.
Absolute Magnitude: Comparison of brightness between stars.
Luminosity: Relationship between size and temperature.
Mass: Measured relative to the Sun's mass
Color/Temperature: Correlation between color and temperature, ranging from red (coolest) to blue (hottest).
Polaris (North Star): Brightest star in Ursa Minor (Little Dipper), almost motionless.

Rotation: Stars rotate on their axes, causing apparent movement.
Revolution: Stars appear to move differently throughout the year due to Earth's revolution around the Sun.

Constellations: 88 recognized constellations, 12 associated with zodiac signs. Based on Greek and Babylonian names.
Uses:
Religious: Used for ceremonies and rituals.
Agricultural: Guided farming practices based on seasonal changes and star patterns.
Navigation: Essential for determining positions at sea or in the air.
Asterisms: Smaller, recognizable patterns of stars within constellations (e.g., Big Dipper in Ursa Major).
Constellation Lines: Used to create visual patterns in the sky.
Circumpolar Constellations: constellations that never set below the horizon for a given location.
Celestial Coordinates: Used by sailors and pilots for navigation.
Celestial Sphere: Imaginary sphere surrounding Earth, onto which stars are projected.
Zenith: Highest point in the sky directly above the observer.
Horizon: Boundary between Earth and sky.
Meridian: Imaginary line from north to south, through the zenith.
Ecliptic: Imaginary line representing the Sun's path across the sky (zodiac signs lie along it).