NATS 1745 Lecture Notes - Lecture 1: Classical Planet, Star Trail, Lunar Phase
15 May 2018
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What can be seen within the night sky
● Stars-positioning
● Planets -Venus, mars, Jupiter, Mercury, Saturn (can be seen by the naked eye)
● Moon- phases
● MIlky way galaxy- glowing bond across sky
● Comets- they change , important in the history of astronomy. (also has caused many
debates
● Meteor
● Sun
● Northern lights- material from the sun makes the earth’s atmosphere glow
Does these objects change? How? How do they move?
● Understanding the motions of objects in the sky is key for understanding the cosmos
● Responsible for driving astronomical knowledge and scientific revolutions throughout history
● Plants move in the sky- big part of ancient history. Also big driving force in science
● The earth rotates every 24 hours on its axis. The earth also revolve around the sun
The Changing the sky
Sun
● Rises in the east and sets in west- reaches highest point on the meridian
● We know the reason for the changing sky/motions in sky. Ancient people didn’t know
● But they were adepts at noticing and measuring
● Become good at predicting future motions
● 2 TYPES OF MOTIONS
○ Daily (diurnal)-
■ object rises in the east and sets in the west
■ Due to rotation of earth about its axis once every 24 hours
○ Yearly
■ Seasons on the earth- sun appears lower in the winter and much higher in
summer ( the height above the horizon changes throughout the sun. locating
of rising and setting Sun changes throughout the year)
■ Height of the sun’s path through day sky is higher, longer in Summer lower,
shorter in winter
■ Different stars are visible in different season (some cases)
■ Yearly motion due to earth revolving or orbiting around the sun
Moon
● Also rises in the east and set in the west.
● The moon goes through phases
Star-
● Visible in the night sky, arranged into patterns or constellation like orion
● Rises in the east and set in the west
● Relative position remains fixed
● Stars move nightly due to Earth's rotation: rise in east and set in west. This image is a star
trail, where the camera shutter has been left open for a period of time. The tracks are the
changing positions of stars as the Earth rotates
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
What can be seen within the night sky. Planets -venus, mars, jupiter, mercury, saturn (can be seen by the naked eye) Milky way galaxy- glowing bond across sky. Comets- they change , important in the history of astronomy. (also has caused many debates. Northern lights- material from the sun makes the earth"s atmosphere glow. Understanding the motions of objects in the sky is key for understanding the cosmos. Responsible for driving astronomical knowledge and scientific revolutions throughout history. Plants move in the sky- big part of ancient history. The earth rotates every 24 hours on its axis. Rises in the east and sets in west- reaches highest point on the meridian. We know the reason for the changing sky/motions in sky. But they were adepts at noticing and measuring. Object rises in the east and sets in the west. Due to rotation of earth about its axis once every 24 hours.
