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Tutorial Course

GCSE Astronomy — Time and the Earth–Moon–Sun Cycles

Led by Hipparchus of Nicaea

1 modules ~7 hours of tutorial Physics & Astronomy Updated today

Module 4 of Edexcel GCSE Astronomy — the largest module in Paper 1. Led by Hipparchus of Nicaea, the astronomer who built the first reliable star catalogue and discovered the precession of equinoxes by comparing his measurements with those a century and a half earlier. The student learns astronomical timekeeping from the sidereal day to the marine chronometer.

Time and the Earth–M…4
  1. Module 4

    Time and the Earth–Moon–Sun Cycles

    Led by Hipparchus of Nicaea

    The question

    What does it mean to "tell the time" astronomically — and how many different times can the same instant be? The spec asks the student to navigate the difference between sidereal and synodic days, between Apparent and Mean Solar Time, between local time and Greenwich Mean Time; to build and apply the Equation of Time; to find local noon and longitude with nothing more than a shadow-stick and a chronometer; to account for equinoxes, solstices, and the annual variation in sunrise; and to understand the eighteenth-century longitude problem and the two methods (lunar-distance, horological) that solved it.

    Outcome

    the student can distinguish all the varieties of astronomical time named in the spec, build and apply the Equation of Time, determine local noon and longitude by shadow-stick, account for equinoxes and solstices and the seasonal variation in the Sun's apparent path, work with time zones and Greenwich Mean Time, and outline the two methods that solved the longitude problem at sea. *(Edexcel 1AS0 Paper 1 — Topic 4, spec points 4.1–4.21)*

    Sub-units

    1. ○ 4.1 Sidereal versus synodic days and months
    2. ○ 4.2 Apparent, Mean, and Local Solar Time; the Equation of Time
    3. ○ 4.3 Shadow-sticks, sundials, and local noon
    4. ○ 4.4 Equinoxes, solstices, and annual variation
    5. ○ 4.5 Time zones and GMT
    6. ○ 4.6 Determination of longitude (lunar-distance and chronometer methods)