To most people, 14th March is nothing but an ordinary day in a year. Yet to mathematics enthusiasts, it is Pi day, 3.14 is also the approximate value of π, Pi....

On 26 December, there was an annular eclipse occurred. However, people could only see the partial eclipse in Hong Kong. What is the partial eclipse? What is the difference between it and annular eclipse? How should we observe this kind of celestial events?