Star Maps – Constellations
SNC1D
Expectations: D2.2, D3.6
Constellations
What is a star?
• A STAR is a large sphere of glowing gases.
• Stars change over time.
– Which is the closest star to Earth?
• THE SUN!
• The sun is a medium sized star
• MUCH, MUCH larger than Earth
Stars as Tools for Navigation
• The North Star is called Polaris and located directly above the
North Pole. This star appears in the same place every night all
year long.
• In the Northern Hemisphere, if you find Polaris you will be able
to tell which direction is north.
• The Southern Hemisphere does not have a star to help you
find its pole. Instead it has what is known as a Southern
Cross.
• The Southern Cross consists of 4 bright stars and some
dimmer ones. All of these together point to the south pole.
Time Lapse – Night Sky - Polaris
The Southern Cross
Seeing the Constellations
Seeing the Constellations
Seeing the Constellations
Directions in the Sky
•
•
•
•
North is toward the North Celestial Pole
South is toward the South Celestial Pole
East is toward East on the ground (usually)
West is toward West on the ground (usually)
A pattern or group of stars
in the sky is called a
constellation.
People of ancient time saw
the constellations as character
or animals in the sky. They
made up stories to explain
how the object, animal, or
character came into the night
sky.
Star Patterns
The Big Dipper
The Big
Dipper
CONSTELLATIONS
• Constellations are
imaginary patterns of
bright stars.
• The ancient Greeks
invented the
constellations we call the
twelve signs of the
zodiac.
Constellations
• A grouping of stars.
• Ursa Major (big bear- can you see the Big Dipper?)
Constellations
• Earth rotates on its axis, this makes most
constellations appear to rise in the east and set
in the west during the night.
• Most constellations appear in many different
positions in the sky as the Earth revolves
around the sun.
• There is a group of stars that appear in the sky
all night long and all year long. It seems that
these stars do not rise and set, but circle the
Earth’s north pole each night. These stars are
called circumpolar.
CONSTELLATIONS CONT.
• There are eighty
eight official
constellations.
• Some examples
are: Big dipper,
Orion, Gemini,
Little dipper.
STAR CHARTS
How can we identify constellations in the night
sky?
The use of a star chart can help us!
A STAR CHART is a map of the stars in the
night sky.
STAR CHARTS
On a star chart, lines often connect the stars
that might make up a constellation.
Different star charts must be used at different
times of the year and in different places on
Earth.
Many stars visible from the Southern
hemisphere cannot be seen from the Northern
hemisphere.
STAR CHARTS
Star Map
• Map of the night sky that shows the positions of the
stars in a particular part of the sky.
• Can be used for navigation. (still used by sailors)
• All stars in the Northern Hemisphere appear to
revolve around Polaris (the North Star).
• The stars close to Polaris are visible all year.
• Example: planisphere displays date and time to
locate stars, constellations and galaxies.
What is a planisphere?
• A planisphere is a
map of the night
sky.
• It helps sky gazers
to figure out where
the constellations
should be.
Before we begin…
• We need to know some common basic
terms, and we need to know
directions.
Horizon
• The horizon is
the place where
earth meets
sky.
Horizon
Zenith
• the point of the
celestial sphere
that is directly
over the observer
and 90 degrees
from all points on
that person's
horizon
• The top of the sky!
Azimuth
• the angular
distance along the
horizon between a
point of reference,
usually the
observer's
bearing, and
another object
How to use a compass…
• A compass always points North.
• Make the compasses on the table line
up with the N.
• Point to East
• Point to West
Ecliptic
• The path across the sky
celestial objects appear
to follow over the year.
Let’s look at the planisphere
Date
Time
The very center of
the circle is the
zenith, the highest
place in the sky;
right above your
head!
Star Wheel copied from
http://www.handsonuniverse.org/activities/uncleal/NorthStarwheel.pdf
Calendars
• Many First Nations groups noted that that the
appearance of certain patterns marked the changing
of the seasons.
• Ancient Egyptian farmers noticed that the annual
flooding of the Nile River, used for crop irrigation
would occur every 365 days when the Sun passed
through the constellation Leo.
• Others lined up stones with the Sun’s path in the sky
and were able to track the start and end of each
season.
Soltices and Equinoxes
• Ancient Mayans built a
giant pyramid that is
aligned to the Sun’s
movement in the sky.
At sunset on the spring
and fall equinoxes, a
corner of the structure
casts a shadow that
resembles a plumed
snake slithering down
the pyramid steps.
Newgrange, Ireland
• On the day of the Winter Solstice, the burial
chamber of Newgrange is illuminated for 17
minutes.
• The ancient Irish used Newgrange for both a
calendar and a sacred building for the
community.
• Newgrange dates from 3000 BC – much
older than the pyramids of Egypt and
Stonehenge in England
Diagram of the passage inside Newgrange of the passage inside Newgrange
Stonehenge
• Circular arrangement of
giant stones and
boulders.
• At sunrise on the
summer solstice every
year, the Sun’s first rays
strike a particular stone.
Other Views
• Some West Coast Natives tell of the stars
being formed when the sleeping Sun’s mouth
spewed sparks through the smoke hole of it
house. As the Sun slept, its brother, the Moon,
rose in the east.
• In other First Nations legends, lunar eclipses
are the result of monsters in the sky
swallowing the Moon.
Azimuth
• The horizontal angular
distance from north
measured eastward
along the horizon.
(North 0º, East 90º,
etc.)
Altitude
• The angular height an
object appears above
the horizon, measured
vertically.
Hand Angles
• Finger 1º
• Fist 10º
• Outstretched hand 20º
Homework
• Planisphere construction
• Using the planisphere, answer the worksheet
questions.