NAV 4 Quiz Number 1 Semi Final

What is the primary purpose of a sextant in navigation?

• Measuring air temperature and atmospheric pressure at sea

• Determining wind speed and direction

• Communicating with other ships using high frequence radio

• Calculating the angle between celestial objects and the horizon

Which part of the sextant allows the user to view both the horizon and the reflected image of a celestial object simultaneously?

• Index mirror

• Horizon mirror

• Telescope

• Micrometer drum

What is the name of the movable arm on a sextant that carries the index mirror?

• Altitude arm

• Index arm

• Reflector arm

• Sight arm

What is the function of the micrometer drum/ vernier scale on a sextant?

• To focus the telescope

• To allow fine adjustments to the angle measurement

• To adjust the position of the horizon mirror

• To calibrate the sextant’s index error

When using a sextant, what is the term for the angle measured between the horizon and a celestial object?

• Azimuth

• Declination

• Zenith

• Altitude

What is the main principle behind the operation of a sextant?

• Single refraction of light

• Double reflection of light

• Double refraction of light

• Single reflection of light

Why are non-correctable errors difficult to deal with in sextant observations?

• They are built into the instrument and cannot be adjusted

• They are caused by temporary environmental conditions

• They can only be corrected by celestial tables

• They change with every observation

What do you call the sum of all non-correctable errors of a sextant?

• Graduation Error

• Collimation Error

• Instrument Error

• Centering Error

What is the certificate issued on a sextant that indicates its total non-correctable error?

• Sextant Certificate

• Calibration Certificate

• Index Error Certificate

• Altitude Correction Certificate

In a sextant, light from a celestial object is reflected twice before reaching the observer's eye. Which components are responsible for these reflections?

• Telescope and arc

• Index mirror and horizon mirror

• Index arm and micrometer drum

• Horizon glass and vernier scale