Principles of Celestial Navigation

Basics » Geographic Position » Exercises

celestial sphere and geosphere showing a star and its corresponding geographic position

What is the Geographic Position (lon, lat) of Star A?

The correct answer is b.

The GP of Star A is 70 degrees W, 45 degrees N. A star's geographic position (GP) = its (west longitude, latitude) = its (GHA, Declination). Note that the order of these coordinates is reversed from the typical (latitude, longitude) values denoting cities, landmarks, or other locations on Earth.

Please make a selection.
celestial sphere and geosphere showing stars and their corresponding geographic positions

Identify the position (GHA, Dec) of each celestial object shown in the image.

Star B    GHA    Dec

Star C    GHA    Dec

Star D    GHA    Dec

Star B    GHA: 90°    Dec: 15°N

Star C    GHA: 40°    Dec: 12°S

Star D    GHA: 20°    Dec: 30°N

Note that because GHA is measured westward from 0 to 360 degrees, the abbreviation "W" to specify direction is not included.