Download Celestial Co-ordinates - Astronomy @ Walton High School

• To use and understand celestial
co-ordinates.
• To explain why Polaris remains fixed in the
sky at an elevation equal to latitude
To use and understand celestial co-ordinates
 In
astronomy, a
celestial coordinate
system is a system for
specifying positions of
celestial objects:
satellites, planets,
 http://www.youtube.c
om/watch?v=1Toya19H
12wstars, galaxies, etc.
 Right
Ascension is the equivalent of longitude in
space.
http://www.youtube.com/watch?v=iGgOS
fYTxFA
 Declination
means the latitude of a star in
the sky measured from the Celestial Equator
which is an extension of our own Equator
 One
of the two points on the Celestial Sphere
where the Ecliptic and the Celestial Equator
cross one another. The First Point of Aries,
which is actually in Pisces, defines the zeropoint for Right Ascension
 Right
Ascension
 How far an object is along the celestial
equator from the first point of Aries (the 0
point for right ascension).
 Declination
 How far north and south an object is from
the Celestial Equator

http://cse.ssl.berkeley.edu/segwayed/lessons/findplanets/coord
inates.html#

http://www.glyphweb.com/esky/concepts/firstpointofaries.html
Use the above website to create a glossary for the following terms:Declination
Right Ascension
Celestial Sphere
Celestial North Pole
Celestial South pole
Celestial Equator
Latitude
Azimuth
Longitude
 You
may hear these terms. From any
location, we can measure how high in the sky
an object is (altitude) in degrees from 0
(horizon) to 90 (zenith). We can also measure
its direction from north (0 to 359°). The
problem with this is that a star's position
changes all the time and from location to
location. For this reason we use Right
Ascension and Declination.
To explain why Polaris remains fixed in the sky at an elevation equal to latitude
Polaris is located at very close to 90 degrees in
the sky. This is the Northern Celestial Pole. If you
stood at the North Pole and looked up, it would
be directly above your head. Because of this we
can find our latitude in the Northern Hemisphere
by measuring the angle of Polaris in the sky.
 Polaris is doubly useful as it appears fixed in the
sky and other stars seem to rotate around it. It
always points north.
 If you were slightly north of the Equator you may
be able to see Polaris on the horizon looking
north.
 From London you can see Polaris at approx 51
degrees north.

 Read
through the task sheet information then
attempt the questions on the following
pages. This is DIFFFICULT, if you are
struggling please let me know.
 State
how you have met the below objectives
• To use and understand celestial
co-ordinates.
• To explain why Polaris remains fixed in the
sky at an elevation equal to latitude