A partial lunar eclipse will be visible in Hong Kong on November 19 (Friday). This is the second lunar eclipse this year, after the first one in May. Members of the public may enjoy this event during the evening when the Moon rises from the east-northeast horizon. At the time of moonrise at 5:38pm that day, the "maximum eclipse" stage has already ended. The Moon is leaving the umbra gradually and the partial eclipse ends at 6:47pm when the Moon exits the Earth's umbra completely. The whole eclipse ends when the Moon leaves the penumbra at 8:06pm.

When the Sun, the Earth and the Moon are aligned, the Moon will enter the Earth's shadow, resulting in a lunar eclipse. The shadow of the Earth can be divided into two parts. Umbra is the area where the sunlight is completely blocked; and penumbra is the area where sunlight is only partially blocked. Depending on how the Moon comes in contact with the Earth's shadow, lunar eclipses can be divided into three types, namely the penumbral eclipse, partial eclipse and total eclipse. A penumbral lunar eclipse happens when the Moon enters the penumbra of the Earth; whereas a partial lunar eclipse happens when only part of the Moon enters the umbra. When the Earth's umbra covers the Moon completely, a total lunar eclipse results. A partial lunar eclipse can be divided into five stages: Moon enters penumbra, Moon enters umbra, Maximum eclipse, Moon exits umbra and Moon exits penumbra.

The fraction of the Moon's diameter covered by the Earth's umbra is called Eclipse Magnitude, and that of partial lunar eclipse is always between 0 and 1. The magnitude of the eclipse on November 19 is 0.97, which means the Moon will almost be completely covered. However, the "maximum eclipse" stage will end before moonrise in Hong Kong, thus only the last two eclipse stages can be seen. For more information on this partial lunar eclipse, please browse the Hong Kong Space Museum's website: https://hk.space.museum/en_US/web/spm/starshine/astroevent/lunareclipse/partiallunareclipse.html