Chapter 3

Locating Places

and Telling time on Earth

Latitude Longitude

Longitude• Lines of longitude, or meridians,

circle the earth from north to south. These lines divide the earth into east and west sections.

• The prime meridian is a line of longitude. It divides the earth into east and west hemispheres (halves). The prime meridian has a longitude of 00 It passes through Greenwich, England.

• Lines of longitude are numbered from 0 to 180 degrees east or west. A location is referenced as east or west relative to the prime meridian.

Latitude • Lines of latitude, or parallels, circle the earth from east to west. These lines divide the earth into north and south sections.

• The equator is a line of latitude. It divides the earth into north and south hemispheres (halves). The equator has a latitude of 0o. 

• Lines of latitude are numbered from 0 to 90 degrees north or south.

• A location is referenced as north or south relative to the equator.

Arctic Circle – 66.33o

Tropic of Cancer – 23.5o

EQUATOR – 00

Antarctic Circle – 66.3o

Tropic of Capricorn– 23.5o

NORTH

SOUTH

Locating Places• Each latitude and

longitude is 15o away from each other.

• Latitude = N or S• Longitude = E or W• 1o = 70 miles• = 112 km• = 60 min• When writing a

location's latitude and longitude, always list latitude first!

• N• 60 45 30 15 0 15 30 45 60

• 60• 45• 30• 15• 0 W E• 15• 30• 45• 60• S

600 N,300 E

450 N,300 W

300 S,450 E

300 N,150 E

300 S,0 Long

0 Lat,450 W

600 S,450 W

Give the Direction

• 43 42

• 60 45 30 15 0

• 65 60

• 45

• 30

• 15

• 64 0

• 122 123

• 0 15 30 45 60

• 51 0

• 15

• 30

• 45

• 52 60

SE NW

51015’ S,1220 30’ E 64030’ N,420 15’ W

1 degree = 60 minutes

• 3 2

• 60 45 30 15 0

• 5 60

• 45

• 30

• 15

• 4 0

• 1 2

• 0 15 30 45 60

• 3 0

• 15

• 30

• 45

• 4 60

4015’ N,20 45’ W

3015’ S,10 30’ E4045’ N,20 15’ W

3045’ S,20 00’E

• When writing a location's latitude and longitude, always list latitude first!

• 50 15 30 45 51 7 45 30 15 6 23 15 30 45 24

• 12 8 45

• 15 15 45

• 30 30 30

• 45 45 15

• 13 9 44•

12015’ S,500 30’ E 80 30’ S,60 15’ W 44015’ N,230 45’ E

Determine the location of the point.• 15 16• 75

• 74

• 39 38• 45

•

• 46

• 150 149• 52

• 53

• 79 78• 67

• 66

74045’ N,150 30’ E

52015’ S,1490 45’ W

45015’ S,380 30’ W

66015’ N,780 15’ W

15 30 45

15 30 45 45 30 15

45

30

15

45

30

15

45 30 15

15

30

45

15

30

45

Plot the points.• 88o30’00” S, 133o15’00”E• 133 134• 88

• 89

• 55o45’00”N, 23o15’00”W• 24 23• 56

• 55

• 48o15’00”N, 162o45’00”E• 162 163• 49

• 48

• 61o15’00”S, 90o45’00”W• 91 90• 61

• 62

45 30 15

15

30

45

45 30 15

45

30

15

Determining Distance from a Point

Prim

e Merid

ian

Equator

Latitude – N or S

Longitude – E or W

Determine the distance

• 1. 88o30’00” S, 133o15’00”E• A. Equator (mi) =

• B. Prime Meridian (Km) =

• C. Tropic of Cancer (mi)• D. 180 long

• 2. 55o45’00”N, 23o15’00”W• A. Equator (km) =

• B. Prime Meridian (mi)

• C. Tropic of Capricorn (km)

• D. 46o45’E

3. 48o15’00”N, 162o45’00”E

• A. Tropic of Cancer (mi)

• B. Arctic Circle (Km)

• C. Antarctic circle

(mi)• D. Equator Mi

• E. Tropic of Capricorn

• 4. 61o15’00”S, 90o45’00”W

• A. Tropic of Capricorn (km) =

B. Antarctic circle (mi) =

• C. Arctic Circle = (mi)

• D. 123o15’W

• E. 45o45’E

Determining Distance

Prim

e Merid

ian

Equator

Problem Solving• Place Z is located

at 600 north. How far in miles is place Z – 1. to the North

Pole?– 2. from the Tropic

of Cancer?– 3. to the Arctic

Circle?

• Give the exact latitude or longitude of the following places:

• 1. 1,190 miles north of the equator

• 2. 1050 miles east of the Prime Meridian

• 3. 1,155 miles south of the equator

• 4. 1750 miles west of the Prime Meridian

Sidereal Days and Solar Days• The sidereal day is defined to be the length of time for

the vernal equinox to return to your celestial meridian. • The solar day is defined to be the length of time for the

Sun to return to your celestial meridian. • The two are not the same, as illustrated in the following

animation.

• Because the Earth is in motion on its orbit around the Sun in the course of a day, the Earth must turn about 4 minutes longer each day (3 minutes and 56 seconds, to be exact) to bring the Sun back to the celestial meridian than to bring the vernal equinox back to the celestial meridian. 

• Thus, the solar day is 3 minutes and 56 seconds longer than the sidereal day. 

• It is this almost 4 minute per day discrepancy that causes the difference in sidereal and solar time.

Time Zone

Universal Time• Like most other

astronomical calculations, scientific predictions are usually presented in terms of Universal Time.

• In order to convert predictions from UT to local time, you need to know what time zone you are in.

International Date Line

• The International Date Line is an irregular line drawn on the map of the Pacific Ocean, near, and in many places coincident with, the 180th meridian.

• It marks the place where navigators change their date by one day on a transpacific voyage.

• East of the line it is one day earlier than to the west.

• The conversion from UT to local time in US is as follows: 

• Atlantic Standard Time 60º (AST) = UT - 4 hours

• Eastern Standard Time 75º (EST) = UT - 5 hours

• Central Standard Time 90º (CST) = UT - 6 hours

• Mountain Standard Time 105º (MST) = UT - 7 hours

• Pacific Standard Time 120º (PST) = UT - 8 hours

• If daylight savings is in effect in the time zone, you must ADD one hour to the above standard times.

• June - DST

• Sample Problem: Let's assume that an eclipse begins in Los Angeles, CA on June 20 at 20:25 UT. Los Angeles is in the , so: 

• Local Time = 20:25 - 8 hours = 12:25 (= 12:25 pm)

• But since Los Angeles observes we must ADD one more hour to the above time.

• So the eclipse will begin at 13:25 (= 1:25 pm) local time. 

Time Zone Chart

Problem 1

• The local time at 750 W is 10 hrs, Calc the time at– A. 0 =– B. 1200 W =– C. 900 E =– D. 1500 W =– E. 1200 E =– F. 600 W

– G. 300 E =– H. 1800

• A. 15 hrs• B. 7 hrs• C. 21 hrs• D. 5 hrs• E. 23 hrs• F. 11 hrs• G. 17 hrs• H. 3 hrs

Problem 2• The local time at 1050 E is 12

hrs and 25 min, Sept 19,2006. Determine the time and date on the following places:

• A. 1650 E• B. Greenwich, England• C. 450 E• D. 900 W• E. 600 W• F. 1800 • G. 750 W• H. 300 E• I. 1500 W

• A. 16:25, Sept. 19• B. 5:25, Sept 19• C. 8:25, Sept 19• D. 23:25, Sept 18• E. 1:25, Sept 19• F. 17:25, Sept 18• G. 24:25, Sept 19• H. 7:25, Sept 19• I. 19:25, Sept 18

Problem 3• The local time at 450 W is 16

hrs and 5 min, Sept 22,2006. Determine the time and date on the following places:

• A. Universal time• B. 1200 W• C. 450 E• D. 1500 W• E. 1050 E• F. 1800 • G. 750 E• H. 1650 E

• A. 19:05, Sept. 22• B. 11:05, Sept 22• C. 22:05, Sept 22• D. 9:05, Sept 22• E. 2:05, Sept 23• F. 7:05, Sept 22• G. 24:05, Sept 23• H. 6:05, Sept 23

PROBLEM 4• The last Islamic terrorist action

on American soil was the bombing of WTC last 9-11-2001. If the attack happens at around 9:05 AM UT, at what time did the bombing occur on the following places?

• A. 60o E • B. 120o W• C. 120o E• D. 60o W• E. 1650 E• F. 1650 W• G. 1800 • H. 300 E• I. 900 W

• A. 13:05, 9/11• B. 1:05, 9/11• C. 17:05, 9/11• D. 5:05, 9/11• E. 20:05, 9/11• F. 22:05, 9/10• G. 21:05. 9/10• H. 11:05, 9/11• I. 3:05, 9/11

Problem 5• The Shoemaker Levy 9

comet hits Jupiter last July 16, 1994. If the delayed telecast will be shown nationwide at 0730 hrs. UT, determine the time that the said event will be shown on the different places.

• A. EST =• B. 139o15’00” E =• C. 82o45’00” W = • D. 58030’00” E =• E. 142o45’00” W =• F. 160030’00” E =• G. 112015’00” W =

• A total solar eclipse will occur on Dec 24 at 1530 hrs GMT in the southern part of the earth.

• A. What is the local time if the eclipse would be observed on the following places?– A. 49o30’00” E– B. 73o45’00” W– C. 157o15’00” E– D. 170o30’00” W

• B. Determine the season.

Problem 6

• The local time at 80015’00”S & 60030’00”W is 10 hrs, Sept 25, find the time and date at on the ffg. Places.

• A. UT• B. 75oE• C. 900 W• D. 165 0 E• E. 135o W• F. 180o

• G. 15o E• Determine the season.• Plot the point

Problem 7

• The local time at 68o45”00’N, 23o15’00’ E is 21:15hrs. Sept 27, 2006.

• A. Calculate the time of the following Longitudes– 1. UT=– 2. 69o15’00” W = – 3. 52o15’00’ E = – 4. 146o30’00” W = – 5. 128o15’00” E = – 6. 168o45’00” W =

• B. Determine the season• C. Determine the distance

from the – 1. Tropic of Cancer (mi)– 2. Antarctic Circle (km)– 3. 35030’00” W (mi)

• D. Plot the point

• A 1. 19:15 hrs Sept. 27• 2. 14:15hrs • 3. 22:15 hrs• 4. 9:15• 5. 4:15 hrs. Sept. 28• 6. 8:15 hrs• B. Autumn• C. 1. 70 x 45.25 = 3167.5 mi• 68o45’• - 23o30’• 45o15’• 2. Antarctic

– 135.25 x 112 = 15148 km

• 68o45’• +66o30’• 135o15’

Problem 8

Problem 9

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