Coordinate systems

What is the Celestial Sphere?

• An imaginary sphere surrounding the Earth on which all celestial objects are placed

• The path which the Sun takes through the celestial sphere in one year

• The line that runs from due north on the horizon to due south

• The bearing of an object taken from true north moving in an easterly direction

What is the Ecliptic?

• The path which the Sun takes through the celestial sphere in one year

• An imaginary sphere surrounding the Earth on which all celestial objects are placed

• The line that runs from due north on the horizon to due south

• The bearing of an object taken from true north moving in an easterly direction

What is Hour Angle?

• The angle of the object measured upwards from the observable horizon

• The path which the Sun takes through the celestial sphere in one year

• The bearing of an object taken from true north moving in an easterly direction

• The time since a star last culminated on the meridian

What is Declination?

• The angle of the object measured upwards from the observable horizon

• The angle of the object measured upwards from the celestial equator

• The bearing of an object taken from true north moving in an easterly direction

• The time since a star last culminated on the meridian

What is Altitude?

• The angle of the object measured upwards from the observable horizon

• The path which the Sun takes through the celestial sphere in one year

• The bearing of an object taken from true north moving in an easterly direction

• The time since a star last culminated on the meridian

What is Azimuth?

• The angle of the object measured upwards from the observable horizon

• The path which the Sun takes through the celestial sphere in one year

• The bearing of an object taken from true north moving in an easterly direction

• The time since a star last culminated on the meridian

What is the Meridian?

• The angle of the object measured upwards from the observable horizon

• The path which the Sun takes through the celestial sphere in one year

• The line that runs from due north to due south and passes through the observer's zenith

• The bearing of an object taken from true north moving in an easterly direction

What is the North Celestial Pole?

• The most northerly point that the Sun passes through on the celestial sphere

• The line that runs from due north on the horizon to due south

• The first point of Ares

• The projection into space of the Earth's geographical North Pole

What is Diurnal Motion?

• The apparent motion of an object due to the daily rotation of the Earth

• The path which the Sun takes through the celestial sphere in one year

• The line that runs from due north on the horizon to due south

• The bearing of an object taken from true north moving in an easterly direction

A star is circumpolar if....

• The star's declination is greater than 90° minus the observer's latitude

• The star's declination is less than 90° minus the observer's latitude

• The star's altitude is greater than 90° minus the observer's latitude

• The star's altitude is less than 90° minus the observer's latitude