Download The sky

Astronomy is a nocturnal activity
1953, T. E. Houck and A. D. Code
The sky above us
Stars dominate the night sky
• Relative positions of stars remains fixed
• The whole pattern revolves around us
• Constellations – patterns in star
distribution
• Constellations vary – related to mythology
• Constellations not real
• 1929 IUA – 88 official constellations
• Every star belongs to a constellation
Orion Constellation
Map of Orion Constellation
The wanderers
• Sun, Moon, planets move relative to stars
• Wander in a narrow band – Zodiac
• Ecliptic
The Zodiac
The Ecliptic
The Celestial Sphere
23.5
Earth’s prograde rotation
Ursa Minor
Precession of Earth’s spin
26,000 years
period
Equatorial Coordinates
Examples
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Orion:
Right Ascension: 5 hours
Declination: 5 degrees
Ursa Major = Saptarshi Mandal
The Great Bear (Big Dipper)
Right Ascension: 11 hours
Declination: 50 degrees
Image Sources
Image Sources
http://fourmilab.ch/yoursky/
Image Sources