Homework Assignment #1: NAME ___________________
Instructions:
Read the link Geographic Projections. Then read appendix 3 on your text book. Now you are ready to complete this homework.
Total (20 points)
Hey guys Appendix III in your book is great it has all the info and the best graphics I have seen on this topic. Still
more on this!
Local noon is the time when Sun reaches its maximum elevation on a given longitude. E.g Prime meridian
England happens at 12:00 GMT
So 360 degrees divided by 24 = 15 degrees per 1 hour of change on local noon. Local noon at Miami is 17:00
GMT. So the longitude of Miami is 80.00 West. Five hours and few minutes difference.
But if you set your clock at 12:00 Miami local noon! Then you sail away and find that next local noon is at 11:00
then (in this case) you have sailed 15 degrees East of Miami so your longitude is 65 degrees west!
Polaris the North Star and the Southern Cross can be used to calculate Latitude. Their elevation on degrees above
the horizon = your Latitude. So if Polaris is 45 degrees above the horizon your Latitude is 45 degrees North!
You do not need a Sextant!
1. From the latitude and longitude list below match the coordinates to the letters on the map. (3 pts)
10 degrees South, 40 degrees West _____
20 degrees South, 100 degrees East _____
20 degrees North, 40 degrees East _____
0 degrees Latitude, 140 degrees West _____
60 degrees South, 40 degrees West _____
2. Identify the following (4 pts):
A circle at 0 degrees Latitude is called the ________________.
A circle at 0 degrees Longitude is called the ________________.
A circle at 180 degrees Longitude is ‘generally’ called the _______________.
3. Answer the following (3 pts):
The maximum value for latitude ______________
The minimum value for latitude ______________
The maximum value for longitude ______________
The minimum value for longitude ______________
4. 1 degree of Latitude or Longitude can be further divided into smaller increments of minutes and
seconds. (2 pts)
How many minutes subdivide 1 degree of latitude? ______________
How many seconds subdivide 1 minute of longitude? ______________
How many seconds subdivide 1 degree of longitude? ______________
5. You use an instrument called a sextant and find the following angles of the North Star or Southern
Cross above the horizon. At what latitude are you for each? (Don’t forget to mention N or S)
(5 pts)
Observation Your latitude
North Star (Polaris) is 5 degrees above horizon
Southern Cross is 23 degrees above horizon
Southern Cross is 89 degrees above horizon
North Star is directly above you
North Star is located on the horizon
6. Using an accurate clock and setting your watch for local noon at your home port, determine your
longitude given the following information: Note: Miami Longitude is 80°W, San Diego Longitude
is 110°W. (Don’t forget to mention E or W) (3 pts)
Observation Your longitude
You leave Miami and local noon shows 11am
You leave Miami and local noon shows 8am
You leave San Diego and local noon shows 2pm
You leave San Diego and local noon shows 5pm
