nav cel. nav. 1-50

• 1. Tide Tables tabulate sunrise and . Tide Tables tabulate sunrise and sunset from latitudes:sunset from latitudes:

• A. 88º N to 88º SA. 88º N to 88º S• B. 60º N to 60º S• C. 76º N to 60º S• D. 47º N to 50º S

• 2. A light observed below the horizon 2. A light observed below the horizon or hidden by obstacles and emits a or hidden by obstacles and emits a glow called:glow called:

• A. Halo• B. Loom• C. Corona• D. Aurora borealis

• 3. In lat. 75º N, dec of sun 15º S, which 3. In lat. 75º N, dec of sun 15º S, which of the following occurs?of the following occurs?

• A. Sun crosses the prime vertical twice• B. Sun will not cross the prime vertical• C. Sun crosses the prime vertical once• D. None of the above

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LAT 75º NDEC 15º S

• 4. In lat. 7º N, dec of sun 0º, which of the 4. In lat. 7º N, dec of sun 0º, which of the following occurs?following occurs?

• A. Sunrise before 0600 hrs• B. Sunrise after 0600 hrs• C. Sunrise at 0600 hrs• D. None of the above

• 5. In lat. 7º N, dec of sun 5º S, which of 5. In lat. 7º N, dec of sun 5º S, which of the following occurs?the following occurs?

• A. Sun will not cross the Prime Vertical• B. Sun crosses the Prime Vertical once• C. Sun crosses the Prime Vertical twice• D. None of the above

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LAT 7º NDEC 5º S

• 6. In lat. 75º N, dec of the sun 16º N, which 6. In lat. 75º N, dec of the sun 16º N, which of the following occurs?of the following occurs?

• A. It is total darkness whole day• B. It is total daylight whole day• C. The sun will be below the horizon whole day • D. None of the above

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LAT 75º NDEC 16º N

• 7. The polar distance can never be 7. The polar distance can never be more than:more than:

• A. 90º• B. 270º• C. 180º• D. 360º

8. Which star in nearest to the earth?. Which star in nearest to the earth?• A. Vega • B. Altair • C. Sun • D. Sirius

• 9. The LHA minus the GHA is:9. The LHA minus the GHA is:• A. Longitude• B. Meridian angle• C. Right ascension • D. None of the above

• 10. This is a small circle parallel to the 10. This is a small circle parallel to the celestial equator:celestial equator:

• A. azimuth circle• B. vertical circle• C. altitude• D. declination

• 11. The time of sunrise when the vessel 11. The time of sunrise when the vessel was at the Tropic of Capricorn on or was at the Tropic of Capricorn on or about Sept. 21.about Sept. 21.

• A. 0818• B. About 0800• C. 0618• D. About 0600

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EQEQ

23°27’N

23°27’S

66°33’N

66°33’S

TROPIC OF CANCER

TROPIC OF CAPRICORN

ARCTIC CIRCLE

ANTARCTIC CIRCLE

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LAT 23° 27’S

Tropic of Capricorn

DEC 0°

• 12. Which of the following is true about 12. Which of the following is true about SHA?SHA?

• A. Angular distance of a star east of Aries • B. Angular distance of a star east of the meridian• C. Angular distance of a star west of Aries• D. Angular distance of a star west of the meridian

• 13. In lat. 40º N, dec 20º N, the sun will:13. In lat. 40º N, dec 20º N, the sun will:• A. cross the prime vertical twice• B. cross the prime vertical once• C. cross the prime vertical when sunrise• D. cross the prime vertical when sunset

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Q’d’LAT 40° N

DEC 20º N

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• 14. When the 14. When the observer is on theobserver is on the equator equator which of the following is true?which of the following is true?

• A. Day and night are equal• B. Day is shorter than night• C. Night is shorter than day• D. Day is longer than night

• 15. In 15. In lat. 40º N, dec 20º Slat. 40º N, dec 20º S, which of the , which of the following occurs?following occurs?

• A. Sun will continuously be below the horizon• B. Day is longer than night time• C. Day is shorter than night time• D. Sun will be touching the horizon whole day

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LAT 40°NDEC 20°S

16. In lat. 5º N, dec 7º N, which of the 16. In lat. 5º N, dec 7º N, which of the following occurs?following occurs?

• A. Sunrise after 0600• B. Sunrise before 0600• C. Sunrise at 0600 • D. None of the above

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LAT 5º NDEC 7º N

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d DEC 7º S

17. In the Nautical Almanac, the GHA for 17. In the Nautical Almanac, the GHA for the sun is tabulated for the:the sun is tabulated for the:

• A. mean sun• B. apparent sun• C. true sun • D. both b & c

• 18. Observed altitude is:• A. apparent altitude corrected for parallax and semi-diameter• B. sextant altitude corrected for parallax and semi-diameter• C. altitude of the sun’s lower limb• D. computed altitude corrected for dip

• 19. The time given in the Nautical 19. The time given in the Nautical Almanac for Meridian Passage is in:Almanac for Meridian Passage is in:

• A. ZT• B. LMT• C. GMT• D. LAT

• 20. Northern lights are also known as:20. Northern lights are also known as:• A. aurora borealis• B. corona• C. aurora australis• D. halo

• 21. A luminous phenomena due to 21. A luminous phenomena due to electrical charges in the atmosphere is electrical charges in the atmosphere is called:called:

• A. corona borealis• B. corona• C. aurora• D. aureole

• 22. Which of the following occur if your 22. Which of the following occur if your vessel was at the Tropic of Cancer on vessel was at the Tropic of Cancer on Sept. 21Sept. 21??

• A. The sun will cross the prime vertical at the horizon• B. The sun will not cross the prime vertical• C. The sun will cross the prime vertical above the horizon• D. The sun will cross the prime vertical below the horizon

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LAT 23° 27’N

Tropic of CancerDEC 0°

• 23. The observer’s Zenith at lat. 60º N is:23. The observer’s Zenith at lat. 60º N is:• A. 60º N of the celestial equator• B. 30º N of the geographical equator• C. 30º N of the celestial equator• D. 60º N of the geographical equator

• 24. The sun will stay at the horizon the 24. The sun will stay at the horizon the whole day if:whole day if:

• A. the observer is at the South Pole on or about June 21• B. the observer is at the North Pole on or about June 21• C. the observer is at the North Pole on or about Dec. 21• D. the observer is at the South Pole on or about Sept. 21

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LAT 90° 00’S

SEPT. 21

DEC = 0º

• 25. What is Right Ascension?• A. Angular distance of a celestial body west of Aries• B. Angular distance of the sun east of the meridian• C. Angular distance of a celestial bodies east of Aries• D. Angular distance of the star east of the meridian

• 26. In the daily pages of the Nautical 26. In the daily pages of the Nautical Almanac the “d” correction is the Almanac the “d” correction is the declination change during:declination change during:

• A. 1200 and 1300• B. 0000 and 1200• C. 2300 and 0100• D. 0600 and 1800

• 27. The height of eye is applied to the 27. The height of eye is applied to the apparent altitude:apparent altitude:

• A. before correcting for index error• B. after correcting for index error• C. after correcting for parallax• D. cannot apply

• 28. The first point of Aries is subtracted 28. The first point of Aries is subtracted from GHA, result is:from GHA, result is:

• A. SHA• B. meridian angle• C. LHA• D. right ascension

• 29. The body touches the prime vertical when the:

• A. latitude is less than the declination with opposite names• B. latitude and declination are equal and same name• C. latitude is more than the declination, same name• D. latitude and declination are equal opposite names

• 30. Observer at the north pole on March 30. Observer at the north pole on March 21, which would occur?21, which would occur?

• A. the sun will continuously be below the horizon during the day• B. the sun will continuously be above the horizon during the day• C. the sun will continuously be on the horizon during the day• D. none of the above

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LAT 90° 00’n

MAR. 21

DEC = 0º

• 31. Observer on the north pole on 31. Observer on the north pole on Sept. 21, which would occur?Sept. 21, which would occur?

• A. the sun will continuously be below the horizon during the day• B. the sun will continuously be on the horizon during the day• C. the sun will continuously be above the horizon during the day• D. none of the above

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LAT 90° 00’n

SEPT. 21

DEC = 0º

• 32. Observer on the North Pole on June 21, which would occur?

• A. the sun will be above the horizon during the day• B. the sun will be below the horizon during the day• C. the sun will be on the horizon during the day• D. none of the above

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LAT 90° 00’n

JUNE. 21

DEC = 23º 27’N

• 33. Observer on the north pole on 33. Observer on the north pole on December 21, which would occur?December 21, which would occur?

• A. The sun will be below the horizon during the day• B. The sun will be on the horizon during the day• C. The sun will be above the horizon during the day• D. None of the above

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LAT 90° 00’n

DECEMBER.21

DEC = 23º 27’N

• 34. Which of the four adjustable errors in Which of the four adjustable errors in the sextant causes side error?the sextant causes side error?

• A. Index mirror not being perpendicular to the frame• B. Telescope not being parallel to the frame• C. Elliptical centering error• D. Horizon glass not being perpendicular to the frame

• 35. The marine sextant is subject to 35. The marine sextant is subject to seven different types of errors, four of seven different types of errors, four of which may be corrected by the which may be corrected by the navigator. An error NOT correctable by navigator. An error NOT correctable by the navigator is:the navigator is:

• A. index error• B. prismatic error• C. perpendicularity of the horizon glass• D. perpendicularity of the index mirror

MARINE SEXTANT• ADJUSTABLE ERROR• 1. Collimation Error• 2. Index Error• 3. Perpendicularity Error ( Horizon )• 4. Perpendicularity Error ( Index )• NON - ADJUSTABLE ERROR• 1. Prismatic Error• 2. Centering Error• 3. Graduation Error

• 36. The difference (measured in degrees) 36. The difference (measured in degrees) between the GHA of the body and the between the GHA of the body and the longitude of the observer is the:longitude of the observer is the:

• A. Right ascension• B. Meridian angle• C. SHA of the observer• D. Zenith distance

• 37. What is the longitude of the 37. What is the longitude of the geographical position of a body whose geographical position of a body whose Greenwich hour angle is 310° 30’?Greenwich hour angle is 310° 30’?

• A. 30° 30’ E• B. 49° 30’ E• C. 120° 30’ W• D. 149° 30’ E

• 38. If the sun’s observed altitude is 52° 38. If the sun’s observed altitude is 52° 50’, the zenith distance is:50’, the zenith distance is:

• A. 38° 10’• B. 37° 10’• C. 47° 50’• D. 127° 10’

• 39. The difference of latitude between 39. The difference of latitude between the geographic position of a celestial the geographic position of a celestial body and your position, at the time of body and your position, at the time of upper transit, is represented by:upper transit, is represented by:

• A. zenith distance• B. co-distance• C. co-latitude• D. altitude

• 40. If the sun’s observed altitude is 28° 40. If the sun’s observed altitude is 28° 12’, the zenith distance is:12’, the zenith distance is:

• A. 62° 48’• B. 151° 48’• C. 61° 48’• D. 43° 12’

• 41. A semi diameter correction is applied 41. A semi diameter correction is applied to observations of:to observations of:

• A. Mars• B. The moon• C. Jupiter• D. All of these

• 42. The error in the measurement of the 42. The error in the measurement of the altitude of a celestial body, caused by altitude of a celestial body, caused by refraction, increases as the:refraction, increases as the:

• A. horizontal parallax decreases• B. observer’s height above sea level increases• C. humidity of the atmosphere decreases• D. altitude of the body decreases

• 43. The arc of a great circle which passes 43. The arc of a great circle which passes through the body and celestial poles is through the body and celestial poles is part of the:part of the:

• A. hour circle• B. diurnal circle• C. observer’s meridian• D. altitude circle

• 44. An amplitude of the Sun in high 44. An amplitude of the Sun in high latitudes:latitudes:

• A. is most accurate before sunrise• B. is most accurate after sunset• C. should only be observed when the sun’s lower limb is above the horizon• D. is most accurate when the sun’s center is observed on the visible horizon

• 45. What is NOT a side of the navigational 45. What is NOT a side of the navigational triangle used in sight reduction?triangle used in sight reduction?

• A. Altitude• B. Zenith distance• C. Co-latitude• D. Polar distance

• 46. The change in the length of the day 46. The change in the length of the day becomes greater as latitude increases becomes greater as latitude increases because of the:because of the:

• A. path of the ecliptic relative to the equator• B. decreasing distance between meridians• C. changing distance between the Earth and the Sun• D. increased obliquity of the Sun’s diurnal circle

• 47. In the horizon system of coordinates 47. In the horizon system of coordinates what is equivalent to longitude on the what is equivalent to longitude on the Earth?Earth?

• A. Altitude• B. Azimuth angle• C. Horizon• D. Zenith distance

• 48. The 48. The prime vertical is the reference prime vertical is the reference point from which the anglepoint from which the angle of which type of which type of observation is measured?of observation is measured?

• A. Sextant angle• B. Azimuth• C. Amplitude• D. Local apparent noon

• 49. What is the great circle of the 49. What is the great circle of the celestial sphere that celestial sphere that passes throughpasses through the the Zenith, the Nadir and the eastern point?Zenith, the Nadir and the eastern point?

• A. Hour circle• B. Principal vertical• C. Celestial meridian• D. Prime vertical

• 50. What is the term used to identify the 50. What is the term used to identify the angular distance between the prime angular distance between the prime vertical and the greatest arc of the vertical vertical and the greatest arc of the vertical circle of the body on the horizon?circle of the body on the horizon?

• A. Azimuth angle• B. Amplitude• C. Altitude• D. Zenith distance