why is the north star of interest to us? do now: using the esrt, determine the distance in miles...
TRANSCRIPT
Why Is the North Star of Interest to Us?
DO NOW: Using the ESRT, determine the distance in miles from NYC to Albany.
Why Do We Care about the North Star?
• The North Star has been used as an aid to chart navigational maps.
• It has also been used to measure astronomical latitude.
• The North Star can only be viewed in the northern hemisphere. Hence, in the northern hemisphere, the angle to Polaris equals your latitude.
Terrestrial Navigation
• Read the paragraphs on page 21-22 of Reviewing Earth Science.
• Do questions 12 – 20 on Part A of page 23-24.
Polaris
Parallel Rays from Polaris
Equator
Polaris
Parallel Rays from Polaris
Equator
Polaris
Parallel Rays from Polaris
Equator
Polaris
Parallel Rays from Polaris
Equator
Equator
Polaris
Parallel Rays from Polaris
Polaris
Parallel Rays from Polaris
Equator
LO
LO = Latitude of the Observer
AP = Altitude of Polaris
AP =LO
The Altitude of Polaris = the Latitude of the Observer
To Polaris
Zenith of the Observer
Observer’s Horizon
Equator
AP
Equator
LO
X
X
Polaris
Polaris: The Current North Star
• Today the Earth’s axis points within one degree of Polaris.
• Polaris appears to be in a fixed position in the sky throughout the year.
• To find Polaris in the sky, locate the Big Dipper and follow the two stars at the end of the basin upward. This should lead you directly to Polaris. It is the last star in the tail of the Little Dipper.
