Total lunar eclipse in Hong Kong on 26 May

^{Lunar eclipse 2019 Photo: ESA}

The public will have an opportunity to observe a total lunar eclipse on 26 May (Wednesday), the same day when the biggest full moon of the year (viz. the “super moon”) appears. The diameter of the moon on that day will be about 7 per cent larger than the ordinary full moon.

The coming total lunar eclipse will begin before moonrise. As the elevation of the moon will be rather low during the eclipse, the event can be best observed at places with an unobstructed view to the southeast if weather permits. Details of the total lunar eclipse are as follows:

^{The total lunar eclipse process on 26 May 2021 Graphic: HKO}

Date	Time	Phenomenon	Elevation	Direction (Azimuth)
May 26 (Wednesday)	6.56pm	Moonrise	-1 degree	East-southeast (113 degrees)
7.01pm	Sunset	-1 degree	West-northwest (293 degrees)
7.09pm	Total eclipse begins	2 degrees	East-southeast (114 degrees)
7.19pm	Maximum eclipse	4 degrees	East-southeast (115 degrees)
7.28pm	Total eclipse ends	6 degrees	East-southeast (116 degrees)
8.53pm	Moon leaves umbra	22 degrees	Southeast (126 degrees)
9.52pm	Moon leaves penumbra	31 degrees	Southeast (136 degrees)

^{Schematic diagram showing elevation and azimuth of the moon during the total eclipse Graphic: HKO}

The total lunar eclipse will begin at 7:09 pm on that day and end at 7:28 pm, with the maximum eclipse occurring at 7:19 pm. During the period of the total lunar eclipse, the moon will not completely vanish but will appear as dull red. This is the result of the blue part of sunlight being scattered away by the Earth’s atmosphere and the remaining red light refracted onto the moon.

Members of the public can watch the lunar eclipse event via a webcast to be jointly provided by the Hong Kong Observatory, the Hong Kong Space Museum, the Ho Koon Nature Education cum Astronomical Centre (sponsored by Sik Sik Yuen) and the Po Leung Kuk Ngan Po Ling College on the following webpage: www.hko.gov.hk/en/gts/event/webcast-20210526.htm.

For the latest weather conditions and the astronomical observation conditions on 26 May, please refer to the 9-day Weather Forecast issued by the Hong Kong Observatory (www.hko.gov.hk/en/wxinfo/currwx/fnd.htm) and the Weather Information for Astronomical Observation webpage (www.hko.gov.hk/en/gts/astronomy/astro_portal.html) respectively.

The next lunar eclipse observable in Hong Kong will be a partial lunar eclipse on 19 November 2021.