ASA 117 – Basic Celestial Endorsement Practice
Exam Questions And Correct Answers (Verified
Answers) Plus Rationales 2025 Q&A
1. What is the purpose of using a sextant in celestial navigation?
| | | | | | | | | |
A. To measure speed
| |
B. To determine latitude and longitude
| | | |
C. To measure the altitude of celestial bodies
| | | | | |
D. To calculate magnetic variation
| | |
A sextant measures the angle between a celestial object and the
| | | | | | | | | |
horizon, called altitude, which is used to find a line of position.
| | | | | | | | | | | |
2. What is the altitude of a celestial body?
| | | | | | |
A. Its temperature
|
B. Its angle above the horizon
| | | |
C. Its bearing
|
D. Its declination
|
Altitude is the vertical angle between the horizon and the celestial
| | | | | | | | | |
body.
|
,3. The Greenwich Hour Angle (GHA) of a celestial body refers to:
| | | | | | | | | |
A. The angle between the equator and the body
| | | | | | |
B. The angle west from Greenwich to the body's hour circle
| | | | | | | | |
C. The declination of the body
| | | |
D. The time at Greenwich
| | |
GHA is measured westward from the Greenwich meridian to the hour
| | | | | | | | | |
circle of the celestial body.
| | | | |
4. Declination in celestial navigation is similar to:
| | | | | |
A. Longitude
B. Latitude
C. Altitude
D. Zenith distance |
Declination is the angular distance north or south of the celestial
| | | | | | | | | |
equator, similar to latitude on Earth.
| | | | | |
5. What is the primary use of the Nautical Almanac?
| | | | | | | |
A. Calculating tides |
B. Providing celestial data for navigation | | | |
C. Determining wind direction | |
D. Predicting weather |
The Nautical Almanac provides daily positions of the sun, moon,
| | | | | | | | |
planets, and stars for celestial navigation.
| | | | | |
6. What is Zenith Distance?
| | |
A. 90° minus the observed altitude
| | | |
B. Altitude plus declination | |
C. The distance to the horizon
| | | |
D. Latitude minus declination | |
Zenith distance is the angular distance from the zenith to the
| | | | | | | | | |
celestial body, used to calculate position.
| | | | | |
, 7. Which time system is used in celestial navigation calculations?
| | | | | | | |
A. Local Standard Time | |
B. Greenwich Mean Time (GMT) | | |
C. Local Apparent Time | |
D. Zone Time |
Celestial navigation calculations use GMT, also called UTC, to
| | | | | | | |
standardize data worldwide.
| | |
8. The intercept method helps determine:
| | | |
A. Variation
B. The difference between observed and computed altitude
| | | | | |
C. The sun’s exact location
| | |
D. Azimuth of Polaris | |
The intercept is the difference between the observed altitude and
| | | | | | | | |
computed altitude. It defines a line of position.
| | | | | | | |
9. The Local Hour Angle (LHA) is used to:
| | | | | | |
A. Measure the altitude of the moon | | | | |
B. Determine local mean time | | |
C. Calculate the position of celestial objects relative to the observer
| | | | | | | | |
D. Compute magnetic variation | |
LHA is the angle between the observer’s meridian and the celestial
| | | | | | | | | |
body’s meridian, essential for sight reduction.
| | | | | |
10. When the sun is on your meridian, what time is it?
| | | | | | | | | |
A. 0600 GMT |
B. Local Apparent Noon | |
C. Civil Twilight
|
D. Morning Watch |
When the sun crosses the observer’s meridian, it is Local Apparent
| | | | | | | | | |
|Noon, the basis for calculating latitude.
| | | | |
Exam Questions And Correct Answers (Verified
Answers) Plus Rationales 2025 Q&A
1. What is the purpose of using a sextant in celestial navigation?
| | | | | | | | | |
A. To measure speed
| |
B. To determine latitude and longitude
| | | |
C. To measure the altitude of celestial bodies
| | | | | |
D. To calculate magnetic variation
| | |
A sextant measures the angle between a celestial object and the
| | | | | | | | | |
horizon, called altitude, which is used to find a line of position.
| | | | | | | | | | | |
2. What is the altitude of a celestial body?
| | | | | | |
A. Its temperature
|
B. Its angle above the horizon
| | | |
C. Its bearing
|
D. Its declination
|
Altitude is the vertical angle between the horizon and the celestial
| | | | | | | | | |
body.
|
,3. The Greenwich Hour Angle (GHA) of a celestial body refers to:
| | | | | | | | | |
A. The angle between the equator and the body
| | | | | | |
B. The angle west from Greenwich to the body's hour circle
| | | | | | | | |
C. The declination of the body
| | | |
D. The time at Greenwich
| | |
GHA is measured westward from the Greenwich meridian to the hour
| | | | | | | | | |
circle of the celestial body.
| | | | |
4. Declination in celestial navigation is similar to:
| | | | | |
A. Longitude
B. Latitude
C. Altitude
D. Zenith distance |
Declination is the angular distance north or south of the celestial
| | | | | | | | | |
equator, similar to latitude on Earth.
| | | | | |
5. What is the primary use of the Nautical Almanac?
| | | | | | | |
A. Calculating tides |
B. Providing celestial data for navigation | | | |
C. Determining wind direction | |
D. Predicting weather |
The Nautical Almanac provides daily positions of the sun, moon,
| | | | | | | | |
planets, and stars for celestial navigation.
| | | | | |
6. What is Zenith Distance?
| | |
A. 90° minus the observed altitude
| | | |
B. Altitude plus declination | |
C. The distance to the horizon
| | | |
D. Latitude minus declination | |
Zenith distance is the angular distance from the zenith to the
| | | | | | | | | |
celestial body, used to calculate position.
| | | | | |
, 7. Which time system is used in celestial navigation calculations?
| | | | | | | |
A. Local Standard Time | |
B. Greenwich Mean Time (GMT) | | |
C. Local Apparent Time | |
D. Zone Time |
Celestial navigation calculations use GMT, also called UTC, to
| | | | | | | |
standardize data worldwide.
| | |
8. The intercept method helps determine:
| | | |
A. Variation
B. The difference between observed and computed altitude
| | | | | |
C. The sun’s exact location
| | |
D. Azimuth of Polaris | |
The intercept is the difference between the observed altitude and
| | | | | | | | |
computed altitude. It defines a line of position.
| | | | | | | |
9. The Local Hour Angle (LHA) is used to:
| | | | | | |
A. Measure the altitude of the moon | | | | |
B. Determine local mean time | | |
C. Calculate the position of celestial objects relative to the observer
| | | | | | | | |
D. Compute magnetic variation | |
LHA is the angle between the observer’s meridian and the celestial
| | | | | | | | | |
body’s meridian, essential for sight reduction.
| | | | | |
10. When the sun is on your meridian, what time is it?
| | | | | | | | | |
A. 0600 GMT |
B. Local Apparent Noon | |
C. Civil Twilight
|
D. Morning Watch |
When the sun crosses the observer’s meridian, it is Local Apparent
| | | | | | | | | |
|Noon, the basis for calculating latitude.
| | | | |
