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  • Partial lunar eclipse in Hong Kong on August 7 to 8

  • Monday, 31st July 2017

A partial lunar eclipse will occur in Hong Kong on the night of August 7 (Monday) and last till the morning of August 8 (Tuesday). As the elevation of the moon will be rather high during the eclipse, most places with an unobstructed view of the horizon to the south and southwest will be suitable for viewing the event if weather permits.

The eclipse will begin at 11.48 pm on August 7 and end at 4.53 am the next morning, with the maximum eclipse occurring at 2.21 am. This partial lunar eclipse has an umbral magnitude of 0.25, meaning that 25 per cent of the moon’s diameter will enter into the umbra (total shadow) of the Earth at the maximum eclipse. Details of the partial lunar eclipse are set out in the following table:

Date Time Phenomenon Elevation Direction (Azimuth)
August 7 (Monday) 6.41 pm Moonrise -1 degree East-southeast (108 degrees)
11.48 pm Moon enters penumbra 51 degrees South-southeast (166 degrees)
August 8 (Tuesday) 1.22 am Moon enters umbra 49 degrees South-southwest (201 degrees)
2.21 am Maximum eclipse 43 degrees Southwest (219 degrees)
3.19 am Moon leaves umbra 33 degrees Southwest (231 degrees)
4.53 am Moon leaves penumbra 15 degrees West-southwest (246 degrees)

Members of the public can watch the whole 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, the Po Leung Kuk Ngan Po Ling College and the Hong Kong Sheng Kung Hui Solar Tower‧Camp on the following webpage: www.hko.gov.hk/gts/event/webcast-20170807.htm

For the weather on August 7 and 8, please refer to the latest 9-day Weather Forecast issued by the Observatory at the following webpage:
www.hko.gov.hk/wxinfo/currwx/fnd.htm

As regards the astronomical observation conditions for that night, please refer to the “Weather Information for Astronomical Observation” webpage:
www.hko.gov.hk/gts/astronomy/astro_portal.html

The next lunar eclipse observable in Hong Kong will occur on January 31, 2018. It will be a total lunar eclipse.

Figure 1
Figure 1  Path of the moon during the partial lunar eclipse on August 7 to 8, 2017 and moon’s contact times with Earth’s penumbral and umbral shadows.
Figure 2
Figure 2  Schematic diagram showing positions (elevation and azimuth) of the moon during the partial lunar eclipse on August 7 to 8, 2017