The Earth Flashcards
5 things required to navigate
REMEMBER: MC TSA
- Map
- Compass
- Timepiece
- Speed
- Altitude
The percentage variable between equatorial and polar diameter
0.3%
What are the Georgraphic poles known as
TRUE NORTH
TRUE SOUTH
The axial tilt of the earth
23.5॰
The seasons throughout the year are as a result of what
AXIAL TILT OF EARTH
Longitude lines are known by what name
MERIDIANS
Longitude lines join from where to where
TRUE NORTH to TRUE SOUTH
A starting place to read longitude lines can be known by which 3 different names
- Prime Meridian
- Grenwich Meridian
- 0॰ Longitude
Longitude lines are referenced by which 2 cardinal points on a compass
EAST or WEST
The opposite side of the world to the starting meridian is known by what name, and how many degrees of reference
- Anti Meridian
- 180॰
Latitude lines are known by what name
PARALLELS
REMEMBER: The “Aaa” sound
LAaaatitude
pAaaarallel
A starting place to read latitude lines is from what location
EQUATOR
Measurements of latitude are measured from the equator by which 2 cardinal points on a compass
NORTH or SOUTH
REMEMBER: LAT sounds like SATurday = S for South
What are the 3 unit references used when referencing the earth on an aviation chart. I.e coordinates of a location on the chart
- Degrees
- Minutes
- Seconds
Latitude can only be from ____॰ South to ____॰ North.
Longitude can only be from ____॰ East or West to ____॰ East or West
- 90॰ South
- 90॰ North
- 0॰ East or West
- 180॰ East or West
Referencing seconds as a fraction
How else can the following coordinates be written when referencing seconds as a fraction
N52॰33’15” E001॰21’55”
N52॰33.25
E001॰21.92
Where seconds are a fraction of 60 seconds i.e. 15/60 for 15 seconds
15 seconds = 0.25
The distance between longitude lines at the equator is MORE, LESS or THE SAME than at the poles
MORE
The Nautical Mile (nm) is a measurement of what
Angle of one minute latitude
(1/60th of a degree)
What is the unit of speed to define 1nm
1 knot
1nm travelled in 1 hour is 1 knot
What is the circumference of the earth given that we know 1nm is a measurement of angle of one minute latitude
21,600nm
Every angle of one minute latitude is 1/60th of a degree and is known as 1nm, with there being 60 minutes in an hour.
There are 360॰ around the earth (earth is a circle)
360 x 60 minutes = 21,600 minutes
1 minute = 1nm
so 21600 minutes = 21600nm
What is the technical term (name) of calculating the distance at the surface of the earth given the variation with latitude
DEPARTURE
What is the formula to calculate the distance (in nm) represented by a change in longitude at other parallels of latitude
dLong x Cos(Lat)
Change in Longitude (minutes) x Cosine of latitude
Each change in degree represents a change in minutes. So where the formula says “change in longitude (minutes)”, if the change in Longitude is from between 020॰West ad 010॰east, going from east to west, the change is 030॰. We now need to multiple 030॰ by 60 minutes (60 minutes in an hour) to obtain the nautical mile distance (REMEMBER - 1nm ∝ 1/60th degree change in angle i.e. 1 minute)
Formula would become (30 x 60) x Cos(Lat)
What is the distance travelled (in nm) between 035॰West ad 035॰east at Latitude of 53॰ North
2527.6nm
**REMEMBER: **
Change in Longitude (minutes) x Cosine of latitude
035॰ WEST back to 0॰ is 35
0॰ to 035॰ EAST is 35
35 + 35 = 70
(70 x 60) x Cos (53) = 2527.6nm
What are the 2 standard units of measurement for non-geographic reference points
- Meter
- Kilometer
What are the 4 imperial units of measurement for non-geographic reference points
- Statue Mile
- Yard
- Feet
- Inches
What is the significance of a Rhumb line and how it crosses meridians
Cross meridians of longitude at the same angle
What is the definition of a Great Circle
Shortest point between two points on the earths surface
The North Star permanently sits above Earths which point
TRUE NORTH
The North star is part of which constellation
URSA MINOR
Navigational directions are always expressed with how many digits
3
Lines of equal magnetic variation are known as what
ISOGONALS
The difference in bearing between True North and Magnetic North is known as what
VAR
(Variation)
Generally speaking, maps and charts are produced with reference to which north, TRUE or MAGNETIC
TRUE