Astronomy Study Guide Unit 2 2 1B The terrestrial latitude of Columbia Sc A 34 degrees North longitude 81 W 2 1B The reference plane for terrestrial longitude and latitude is A The Earth s geographic equator 2 1D If you are located at the equator the North Celestial Pole has an altitude of degrees above the northern horizon 2 1D If you are located at 34 degrees north the North Celestial Pole has an altitude of degrees above the northern horizon A 0 A 34 If you are located at degrees north the North Celestial Pole has an altitude of whatever degrees you are located at above the northern horizon 2 2C The path that the Sun traces out with its annual motion is termed the 2 2B The vernal equinox the Sun A crosses the equator from S N A ecliptic 2 2C The ecliptic is A The Sun s apparent path against the background stars 2 2D The celestial equator is the A projection of the Earth s equator onto the sky 2 2D The is the projection of the Earth s equator onto the sky A celestial equator 2 2E The projection of the Earth s axis of rotation onto the celestial sphere is termed the poles A celestial A ecliptic A hour A meridian A horizon A equator A equator 2 2E The projections of the axis of the Earth s orbital plane onto the celestial sphere are termed the poles 2 2F Any circle on the celestial sphere that passes through the north and south celestial poles is called a n circle 2 2F The meridian A passes through the observer s zenith 2 2G The circle on the celestial sphere passing through the celestial poles and your zenith is called your 2 2H Which of the following planes circles is perpendicular to the zenith for all observers 2 3 Which coordinate s is are measured in degrees minutes and seconds A Azimuth Altitude Declination All but the Right Ascension are measured in these units 2 3 The coordinate Right Ascension is usually measured in A hours minutes seconds 2 3 In which astronomical coordinate system does the value of both coordinates for a star remain essentially constant during a single night 2 3 The celestial coordinate system based upon the celestial equator with the vernal equinox as a reference direction is the system 2 3 Right Ascension and declination are from what coordinate system A equator system 2 3 The coordinate altitude is usually measured in A degrees minutes seconds 2 3 The coordinate altitude is from the system 2 3 The reference plane of the equator system is the celestial equator and the reference point is the vernal equinox A Horizon A correct 2 3 In the horizon system the altitude of a star remains fixed while the azimuth changes in time A wrong both change with time 2 3 The coordinate declination is usually measured in A degrees minutes seconds 2 3 The reference plane for the horizon system is the horizon and the reference point is the vernal equinox A No the reference point is the north point 2 3 The reference direction in the Horizon System is the 2 3 The coordinate azimuth is from the system 2 3 Right Ascension is used in which coordinate system A north point A Horizon A equator A local meridian 2 4A Hour angle is measured from the along the celestial equator 2 4A The hour angle of a start is measured from the local meridian to the east to the foot of the hours circle passing through the object in question A wrong to the west 2 4B The best coordinate system to use for night to night observations of the stars is the system 2 4C If a telescope uses hour angle and declination it is said to have a n mount 2 4C A telescope with an equatorial mount uses the coordinates A hour angle and declination 2 6 The fact that the star Vega not Polaris will be the north Pole Star around 12 000 years from now is a result of A the precession of the Earth s axis of rotation 2 6 Precession causes Right Ascension to change 2 6 The periodic motion of the Earth s celestial pole with respect to the stars is termed A equator A equatorial A correct A Precession 2 6 If the stars were not moving with respect to the solar system their RA and Declination would be constant on a yearly average A wrong the precession of the Earth s axis causes both to change 2 6 The fact that Polaris was not the Pole Star around 3000 B C can be explained as follows A The axis of the Earth s rotation precesses and pointed in a different direction in 3000 B C from the direction it points to at present 2 6 Which of the following statements is true about Polaris the North Star A It appears near the North Celestial Pole now but has not always been the Pole Star 2 7A Astronomical time is defined as the A Hour angle of the reference object 2 7B Atomic time is based upon radiation from cesium 133 atom A correct 2 7B The Earth s rotation is constant enough to use it as a time reference for all applications not just astronomical A Wrong enough irregularities occur that we now often define time using atomic clocks 2 7C The time based on the motions of the major planets is called time 2 7C time is a time system based upon the motions of the major planets in the solar system A ephemeris A ephemeris A apparent solar 2 7D The interval between sunrise to sunrise is the definition of the day 2 7D The day is the interval between successive transits of the vernal equinox A sidereal 2 7e Universal time is A The local mean solar time at Greenwich UK 2 7F solar time is the hour angle of an average Sun plus 12 hours A mean 2 8A At the vernal spring equinox the Sun A crosses the equator from the S N 2 8A The Sun crosses the Celestial Equator going North on or about March 21 This is known as the spring or vernal 2 8B The occurs when the Sun is in its most northerly position 2 8C The occurs when the Sun crosses the celestial equator going South 2 8D The occurs when the Sun is in its most southerly position A equinox A summer solstice A Autumnal equinox A winter solstice