Blackboard HW: Celestial Navigation

Zenith is defined as ____________________.

90° above the observer, perpendicular to the horizon.

The true bearing to a star from the observer is referred to as:

Azimuth.

Other than deriving visual lines of positions, select two uses for celestial navigation?

Calculating sunrise/sunset and moonrise/moonset. Determine compass error.

What are the three vertices of the Celestial Triangle?

Celestial pole, Celestial body's position, Observer's zenith

Correct symbology for a celestial fix.

Circle.

What term is used to measure "latitude of a celestial body" on the celestial sphere?

Declination.

Celestial navigation assumes the Sun is the center of the celestial sphere.

False.

The altitude-intercept method compares height apparent (Ha) to height observed (Ho) in order to determine where the celestial line of position should be plotted.

False.

A Celestial Body's location as projected down to the Earth's surface is referred to as a:

Geographic Position.

Which is NOT an expression of celestial height (altitude)?

He - Height expected.

What publication is produced in conjunction between the U.S. Naval Observatory and the U.K. Hydrographic Office and provides primary source of ephemeral data required to solve the celestial triangle?

Nautical Almanac.

The Celestial Triangle's three vertices (Celestial Pole, Zenith and Celestial Body) are equivalent to which three points on the Navigational Triangle?

North or South Pole, Assumed Position, Geographic Position.

In order to be used properly, a sextant's Index Error must be measured by:

Observing a flat-sided object or horizon, moving the arm until both images line up and reading off the error on or off the arc.

If you stood at the North Pole, which Celestial body would be at your Zenith?

Polaris.

What are the three vertices of the navigational triangle?

Pole, Celestial body's geographic position (GP), Assumed position

Celestial Navigation is not used to:

Prevent GPS failures.

Which celestial navigation software does the U.S. Navy use?

STELLA.

For the purposes of Celestial Navigation, all Celestial Bodies are located on a second, infinitely large sphere called:

The Celestial Sphere.

For the purposes of Celestial Navigation, what is assumed to be at the center of the Universe?

The Earth.

Celestial Navigation relies on the ability to directly measure:

The angle between the visible horizon and celestial bodies.

Declination is:

The angular distance of a celestial body North or South of the Equinoctial.

Celestial lines of position can be taking during daylight hours.

True.

Circles of equal altitude produce a line of position (LOP).

True.

We use the altitude-intercept method to plot celestial lines of position because circles of equal altitude are too large to plot on most charts.

True.

If height observed (Ho) is greater than height computed (Hc), the ____________________.

the LOP is drawn perpendicular along the azimuth toward the GP