Geography 10
Finding Latitude and Longitude
Ms. Ripley
Name:______________________
Finding latitude and longitude in the Northern Hemisphere
Instructions: Using the diagrams and description answer the following:
1. Explain what each of the following diagram shows.
2. What instrument is used to measure the altitude of stars, planets and the sun?.
At different latitudes the stars and the sun appear at different altitudes in
the sky. For any point in the Northern Hemisphere, the altitude of the North Star
is equal to the latitude of the observer. For example, at the North Pole, latitude
90°N, the North Star is in the zenith. Its altitude is 90°N. At New York City,
latitude 41 °N, the North Star’s altitude is 41°. A captain of a ship observing the
North Star at an altitude of 46° knows that the ship is in latitude 46°N. The
instruments used to measure the altitude of stars, planets and the sun are the
sextant and octant.
Latitude is found in the daytime from the sun’s noon position in the sky. The
sextant (or octant) is used to measure the sun’s altitude. The nautical almanac or
air almanac is then consulted. It shows in which latitude the sun has the observed
noon altitude on the day of observation.
Geography 10
Finding Latitude and Longitude
Ms. Ripley
Name:______________________
Section 2:
Read the short article on Greenwich and answer these questions:
1. In which country is Greenwich?
2. Why would a tourist want a photograph of herself in Greenwich?
3. What latitude is Greenwich?
4. What is the link between Greenwich and a watch?
Greenwich, Where the East Meets the West
ByNinoLoBello
Greenwich, England—This is the place where every tourist plays the same
camera game—in utter delight he stands with one foot in the Western Hemisphere
and the other foot in the Eastern while the shutter clicks.
On a map run your finger to zero longitude (the Prime Meridian) and then to
the latitude that reads 41 degrees, 28 minutes and 38 seconds North. That, folks,
is the spot where East meets West. The place is Greenwich, a metropolitan borough
of London where, on top of a hill at the old Royal Observatory you will find the line
that divides the hemispheres. This is the position from which Greenwich Mean Time
is derived.
The line splitting the two hemispheres is invisible, by the way. But in the
forecourt of the observatory in front of one of the buildings there is the
embedded brass strip that runs up to the wall, ending at a sealed glass door.
Everybody who comes to see for himself predictably has his photograph taken
straddling the line with one foot in each hemisphere. Even reporters have been
known to do it.
Because clocks in the world are set in relation to Greenwich Mean Time,
when you get here don’t let a minute go by. Can you think of a better place on earth
to set your own watch? You can either regulate your timepiece from a 24-hour clock
on the wall outside the observatory or from one that is inside which runs according
to an atomic clock that is accurate down to thousandths of millionths of a second.
Geography 10
Finding Latitude and Longitude
Ms. Ripley
Name:______________________