851) It is the sextant error when the horizon and the index mirror are not parallel index error
852) This is the result when the rays of light passes from one medium to another of different density refraction
853) This is the result when the rays of light passes from one medium to another of different density refraction
854) In order to remove side error from a sextant, you should adjust the __________. horizon glass to make it perpendicular to the sextant frame
855) Index error of a sextant is primarily caused by __________. the horizon glass not being parallel to the index mirror
856) On 16 January 1981, you take a sight of a star. The sextant altitude (hs) is 4°33.0'. The temperature is -10°C, and the barometer reads 992 millibars. The height of eye is 42 feet. The index error is 1.9' off the arc. What is the observed altitude (H 4°17.0'
857) When correcting the sextant altitude to apparent altitude you are correcting for inaccuracies in the reference level and __________. for inaccuracies in the instrument
858) Astronomical refraction causes a celestial body to appear __________. higher than its actual position
859) It is the sextant error if the horizon mirror is not perpendicular to the plane of the instrument side error
860) Parallax is caused by __________._______ being on the surface of the earth rather than in the center
861) The first chronometer used in navigation was tried at sea, in the year of__________. 1735
862) The angular distance of the body above the rational horizon. An arc of the vertical order which passes through the body contained between the rational horizon and the body is called __________.____ True altitude
863) What is the formula of amplitude? Sine A = sine decl x sine lat
864) The depression of the visible horizon below the plane of the sensible horizon dip
865) The depression of the visible horizon below the plane of the sensible horizon. dip
866) A phase correction may be applicable to correct the sextant altitude correction of __________. some planets
867) In what order should the following sextant adjustments be made? I. Make telescope parallel to frame of sextant. II. Set horizon glass perpendicular to frame of sextant. III. Make index mirror and horizon glass parallel when index arm is set at zero. IV, II, III, I
868) The index error is determined by adjusting the __________. micrometer drum
869) When the index and horizon mirrors of a properly adjusted sextant are at an angle of 45° to each other, the arc reads __________. 90°
870) When using horizontal sextant angles of three objects to fix your position, an indeterminate position will result in which situation? A circle will pass through your position and the three objects.
871) Which is a nonadjustable error of the sextant? Centering error
872) Which of these sextant errors is nonadjustable? all of the options
873) On 14 April 1981, a back sight is taken of the upper limb of the Sun as seen in the telescope. The height of eye is 45 feet. The index error is 2.5' on the arc. The sextant altitude (hs) is 117°14.6'. What is the observed altitude (Ho)? 63°09.9'
874) The error in the measurement of the altitude of a celestial body, caused by refraction, increases as the __________. altitude of the body decreases
875) The height of eye correction is smaller than geometrical dip because of __________. terrestrial refraction
876) The parallax of the Moon is greatest when the Moon is __________. on the horizon at perigee
877) What is the major problem with taking high altitude observations? It is difficult to establish the point where the sextant is vertical to the horizon.
878) Where do you find the semi diameter correction to be used to correct sextant observations of the stars? No semi diameter correction is used.
879) It is the sextant error on the index mirror when not perpendicular to the plane of the instrument perpendicularity
880) It is the sextant error on the index mirror when not perpendicular to the plane of the instrument. perpendicularity
881) Which is a non-adjustable error of the sextant? Centering error
882) This is a sextant error exists when the axis of the telescope is not parallel to the plane of the instrument. Collimation error
883) In a sextant, when the telescope is not parallel to the frame, the error is called __________? collimation error
884) This is a correction to the sextant altitude applied to the visible horizon to obtain the sensible horizon dip
885) There are seven sources of error in the marine sextant. Some of them are adjustable, some are not. Which of the following is adjustable? Error of collimation
886) The sextant error of a marine sextant when the index arm set to zero and the reflected image in the actual horizon is in a continuous line is__________. no error
887) The parallax angle will vary the most with the time of year for __________. Venus
888) The Moon is nearest to the Earth at __________. perigee
889) The planet Venus can be observed in the morning before sunrise if it is well to the __________. west of and higher than the Sun
890) The same side of the Moon is always toward the Earth, but more than half of its surface has been seen due to libration. Libration in latitude occurs because __________. the axis of rotation is tilted about 6.5° to the axis of revolution
891) The spinning of a celestial body about its axis is known as __________. rotation
892) The apparent path of the sun around the earth ecliptic
893) Planets whose orbits larger than that of the earth's orbit are classified as superior planets
894) One parsec is equal to ______ 3.26 light year
895) Our solar system including our planet earth is about__________. 4.5 x 10 to the 9th power years
896) By KEPLER second law, the Earth travels faster when nearest to the Sun (December Solstice). This means Northern Hemisphere astronomical winter is shorter than its summer by __________.__________._ 7 days
897) Regressions of the nodes introduces certain irregularities in the processional motion known as _________ nutation
898) Regressions of the nodes introduces certain irregularities in the processional motion known as. nutation
899) Planets whose orbits larger than that of the earth's orbit are classified as superior planets
900) A lunar day average 24h 50m, while a lunar month commonly called a synodical month last ________ 29 1/2 days
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