3. The North Celestial Pole
(NCP)
Special spot on the sky that the Earth’s
rotation axis points to
Why special?
During the night the stars
appear to rotate around
this spot
Also special (and useful) in other ways …
8. Lucky Breaks!
The star Polaris is amazing close to
NCP (now)
The “pointer stars” in the Big Dipper
line up directly with Polaris!!!!
Big Dipper is circumpolar
constellation
–See it all night and all year
Polaris also called Pole Star, North
Star
10. Why care about finding Polaris?
The direction of Polaris is due North
The angle between Polaris and the
horizon is YOUR LATITUDE
How can I measure angles?
14. Astronomy Picture of the Day (APOD)
http://antwrp.gsfc.nasa.gov/apod/ap090627.htm
l
Summer Triangle
http://antwrp.gsfc.nasa.gov/apod/ap090912.html
Winter Hexagon
http://antwrp.gsfc.nasa.gov/apod/ap021106.html
17. Constellation Facts
Group of stars all in roughly the same
direction from Earth, BUT …. Each has
its own different distance from the
Earth
– Therefore, NOT grouped together is space
From Greek astronomers have
inherited the names of the
constellations: mythological figures or
animals
Different cultures on Earth each have
different names for the constellations
19. Visible Constellations change over a
year
May have heard …
– “Orion is a winter constellation”
– “You can see Cygnus most of the summer”
Above comments arise because you
cannot see the Constellations near
where the Sun is in the sky
– Sun so bright it washes out rest of stars
Since Sun moves along the Ecliptic
over a year the constellations “away”
from the Sun change over a year.
21. The Zodiac
Band of constellations closest to the
Ecliptic (Sun’s yearly path across the
sky)
Correspond to Horoscope “Signs”
–Astrology used to make predictions (not
science!)
Useful for backyard astronomy:
Planets and the Moon can always be
found in the Zodiac
Width of the Zodiac belt ~ 18°
