Multiple Choice Questions Positional Astronomy Multiple Choice Questions

Test Question Does this quiz work? A. Yes B. No

Positional Astronomy 1. An arc of length ‘S’ is a section of the circumference of a circle of radius ‘r’ and S subtends the angle θ. Which of the following is the correct relation between S, r and θ? θ = S/r in radians. Y θ = r/S in degrees. θ = S/r in degrees. θ = r/S in radians.

Positional Astronomy 2. Which of the following is a correct statement? Both longitude and latitude lines are great circle arcs. Both longitude and latitude lines are small circle lines. Longitude lines are great circle arcs and latitude lines are small circle lines. y Longitude lines are small circle lines and latitude lines are great circle arcs.

Positional Astronomy 3. Which of the following is a correct statement? Longitude measurements are positive for points west of the Greenwich Meridian and negative for points east of it. Longitude measurements are positive for points east of the Greenwich Meridian and negative for points west of it. y Latitude measurements are positive for points west of the Greenwich Meridian and negative for points east of it. Longitude measurements are positive for points east of the Greenwich Meridian and negative for points west of it.

Positional Astronomy 4. What is the definition of the nautical term ‘knot’? One knot is the time it takes to travel one nautical mile. One knot is double the rate of 3 nautical miles per 6 hours. Y One knot is half the rate of 3 nautical miles per hour. One knot is the time it takes to travel one mile.

Positional Astronomy 5. If a star has a parallax angle of 0.25”, how far away is it? 0.25 parsecs. y 0.25 AU. 4 parsecs. 4 AU.

Positional Astronomy 6. In what direction do the stars appear to move around Polaris? Clockwise. Anti-clockwise. y

Positional Astronomy 7. The vernal equinox is defined by… A time when there are lots of druids at Stonehenge. The date when the sun is at the zenith of a point at the equator in Autumn. The date in spring when the sun is at the zenith of the point halfway between the tropic of cancer and the equator. The date in spring when the sun is at the zenith of a point at the equator. y

Positional Astronomy 8. In the Alt-Az coordinate system where are the respective coordinates measured from? Altitude measured from North Point, Azimuth measured in the fundamental plane from the observer’s horizon. Altitude measured from Celestial equator, Azimuth measured in the fundamental plane from the observer’s horizon. Altitude measured from celestial equator, Azimuth measured in the fundamental plane from the Greenwich Meridian. Altitude measured from observers horizon, Azimuth measured eastwards from the observer’s meridian. y

Positional Astronomy 9. Right ascension could replace Hour Angle in the HA-dec system to produce another meaning full coordinate system, true or false? True. y False. Not enough information to tell.

Positional Astronomy 10. A woman walks due east from Glasgow and after a long time arrives back exactly where she originally started. What could her path be called? A great circle arc. A pilgrimage to Inverness. A small circle. y None of the above.

Positional Astronomy 11. In the spherical sine formula, all of the denominators can be switched around with all of the numerators and still make sense, true or false? True. y False.

Positional Astronomy 12. Which is a correct expression for the spherical cosine formula? Cos(a) = cos(b)cos(a) + sin(b)sin(C)cos(A). Cos(a) = cos(a)cos(c) + sin(b)cos(C)cos(A). Cos(a) = sin(b)sin(c) + sin(b)sin(c)cos(A). None of the above. y All of the above.

Positional Astronomy 13. The Sun’s diurnal path is exactly 180 degrees whatever the time of year for a stationary observer, true or false? True. False. y

Positional Astronomy 14. Which of these statements is FALSE? Sundials would quickly go out of sink if they were compared with an accurate watch. None of these are false. y The days are longer in summer than they are in winter. The ecliptic isn’t parallel to the celestial equator.

Positional Astronomy 15. Which is longer, the sidereal day or the solar day? Sidereal day. Solar day. y They are both the same.

Positional Astronomy 16. The solar day is how much longer than the sidereal day and why? 4 minutes longer because the earth has moved about 1 degree further on its orbit. y 5 minutes longer because the earth has moved about 1 degree further on its orbit. 4 minutes longer because the original measurements on the length of a day when the Gregorian calendar was created were not as accurate as present day measurements. 5 minutes longer because the original measurements on the length of a day when the Gregorian calendar was created were not as accurate as present day measurements.

Positional Astronomy 17. What is the correct form of the equation of time? Equation of time = RA (mean Sun) – RA (true Sun). Y Equation of time = HA (mean Sun) – RA (true Sun). Equation of time = RA (true Sun) – RA (mean Sun). Equation of time = HA (true Sun) – RA (mean Sun).

Positional Astronomy 18. Which is longer the sidereal year or the tropical year? Sidereal year. Y Tropical year. They are both the same.

Positional Astronomy 19. Which statement about the moon is FALSE? The Moon has one side which is never viewable from earth. The Moon takes one sidereal month to orbit the Earth. The Moon has a permanent dark side. y The Moon’s orbit isn’t aligned with the ecliptic.

Positional Astronomy 20. Which statement about planetary configurations FALSE? An inferior planet on the observer’s meridian at midnight is in opposition. A superior planet can never be in opposition. A planet lying in the same direction as the Sun is said to be in opposition. An inferior planet can be in superior or inferior conjunction. y

Positional Astronomy 21. Which statement about planetary configurations is FALSE? An superior planet can have an elongation between 0 and 180 degrees. Quadrature is when the elongation of a superior planet is 90 degrees. Quadrature is when the elongation of an inferior planet is 90 degrees. Y An inferior planet has zero elongation when in conjunction.

Positional Astronomy 22. Which is the correct definition of phase? The angle defined at the Sun between the Earth, the planet and the Sun. The angle defined at the Planet between the Earth, the planet and the Sun. y The angle defined at the Earth between the Earth, the planet and the Sun. None of the above.