Nvg Met Flashcards

1
Q

Which astronomical factors have an effect on the night illumination?

A

Sun elevation
Moon elevation
Moon phase
Other sources of natural light

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2
Q

Which meteorological factors have an effect on the night illumination?

A

Clouds
Percepitation
Ground conditions

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3
Q

Define the term “Civil twillight”

A

The time after SS and before SR when the sun is up to 6 deg below the horizon

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4
Q

Define nautical twillight

A

When the sun is 6 up to 12 deg below the horizon.

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5
Q

Dark night condition after sunset?

A

When the sun is more than 16 deg below the horizon

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6
Q

Explain moon brightness

A

Brightness of the horizontal ground caused by the moonlight, NOT the brightness of the moon itself.

Given in % of the full-moon-light at the average moon-earth distance in case of full zenith.

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7
Q

Explain meteorological optical range, MOR

A

The horizontal distance on which an attenuation of white light by 95% takes place.

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8
Q

Write down the limiting value for the nvg range for flights with night vision goggles.

A

1,5km nvd range
0,5 mlx

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9
Q

Explain chlorophyll effect

A

High degree of reflectivity in near IR WAVELENGTH, ex grass and leaves.

Good quality of NVG image in seasons when bushes and trees have leaves

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