Nsi Study Guide 2

Front 1

The human eye is only sensitive to energy in the visible spectrum ( ___ to ____ __________)

Back 1

400 to 700 nanometers

Front 2

NVDs system specific spectral sensitivity in the ____,____, and ___ IR spectrum.

Back 2

Near Mid and Far

Front 3

Energy is constantly being ________ or _________ by all objects in view.

Back 3

Radiated or Reflected

Front 4

Below __ _______ the background is dominated by reflected and scattered solar or lunar radiation.

Back 4

3 microns

Front 5

Beyond __ _______ the background becomes dominated by _______ ____ ________ that is proportional to the ________ of the ______ _______.

Back 5

4 microns

Terrain self emission

Temperature

Terrain objects

Front 6

The Gen 1 FLIR system operates in the __ to __ ______ range of the EM spectrum.

Back 6

8 to 12 micron

Front 7

NVGs receive illumination from both _______ and _________ sources

Back 7

Natural and Artificial

Front 8

The amount of light generated from a source is called?

Back 8

Lux or Lumens per square meter

Front 9

The relationship between illumination and liminance

Back 9

Albedo

Front 10

One Nano meter is equal to

Back 10

One billionth of a meter

Front 11

1 micrometer is equal to

Back 11

1 millionth of a meter

Front 12

Thermal energy is produced when...

Back 12

Object absorbed energy from IR sources such as sun or warm air

Front 13

Radiation. That strikes and object can be ________, _________, or _________

Back 13

Absorbed, Transmitted, Reflected

Front 14

_______ and __________ thermal source create the thermal scene.

Back 14

Natural and Fabricated

Front 15

FLIR system typically operates in the _____________ or ____________ band of the EM spectrum.

Back 15

Mid IR (3-5 microns)

Far IR (8-12 microns)

Front 16

What is a Photon

Back 16

Particles of energy

Front 17

All objects with a temperature above ________ _____ emit _______.

Back 17

Absolute Zero

Energy

Front 18

Factors that determine how an object appears on the FLIR

Back 18

Temperature, Thermal History, Emissivity, Thermal Mass, and Thermal Inertia

Front 19

Four principal sources of thermal energy

Back 19

Solar Energy

Fuel Combustion

Frictional Heat

Thermal Reflection

Front 20

Definition of Emissivity

Back 20

The ability of an object to emit thermal energy compared to a black body at the same temperature.

Front 21

Definition of a Black body

Back 21

The perfect absorber and emitter of radiant energy

Front 22

Definition of Thermal Mass

Back 22

The ability of an object to store heat

Front 23

Thermal mass is determined by

Back 23

A materials temperature, mass and composition

Front 24

Thermal inertia is

Back 24

A measure of the rate at which o jets change temperature.

Front 25

Thermal Resistance

Back 25

Determines the rate at which heat will flow

Front 26

Three Major factors that influence NVD performance

Back 26

Illumination/ Thermal scene

Terrain Contrast

Atmospheric Conditions

Front 27

The moon reflects about ___ of the sunlight that strikes it

Back 27

7%

Front 28

The amount of light provided by the moon is influenced by what four factors

Back 28

Lunar Cycle

Moon Angle

Lunar Albedo

Variation in Earth Moon Distance

Front 29

How long is a lunar month?

Back 29

29.5 days

Front 30

Moon phases are influenced by...

Back 30

Time of year

Global Position

Front 31

Moon angle is...

Back 31

The angular altitude of the moon with respect to the horizon

Front 32

The moon is about ____ brighter during the _____ _______ (________)

Than it is during the _____ _______ (_______) due to difference in the lunar surface.

Back 32

20%

First quarter : Waxing

Third quarter : Waning

Front 33

The changes in illumination because of earth moon distance is ____?

Back 33

26%

Front 34

On a moonless night _____ of______ is provided by emissions.

Back 34

40%

Front 35

What is airglow

Provides approximately ______ ____ illumination to the night sky.

Back 35

Atoms and molecules in the upper atmosphere

0.00178 lux

Front 36

Starlight provides how much illumination to the night sky?

Back 36

0.0022 lux less than 1/10 of a quarter moon

Front 37

Aurora are...

Back 37

Luminous rays, ribbons, and arch patterns caused by charged particles

Front 38

Gegenscheins are...

Back 38

Faint light caused by sunlight reflecting off of air particles

Front 39

Zodiac lights are...

Back 39

Faint eliptical disks around the sun caused by reflection of particulate matter

Front 40

Noctilucent clouds are...

Back 40

Usually colored, thin clouds with unknown origin.

Front 41

What are the 6 night sky illumination sources

Back 41

Airglow

Starlight

Auroras

Gegenscheins

Zodiac Lights

Noctilucent Clouds

Front 42

Three types of Twilight are...

Back 42

Nautical

Civil

Astronomical

Front 43

Civil twilight is __-__° below the horizon

Nautical twilight is __-__° below the horizon

Astronomical twilight is __-__° below the horizon.

Back 43

0-6

6-12

12-18

Front 44

NVGs are most effective following ____ when the sun has set at least ___ or greater below the horizon.

Back 44

EENT

12°

Front 45

The three primary terrain factors for proper NVG mission planning are...

Back 45

Terrain reflectivity (albedo)

Terrain Contrast

Terrain Shadowing