Mid-Autumn full moon to coincide with lunar eclipse

9 September 2016

The Mid-Autumn Festival this year falls on September 15 (Thursday) and the full moon (Note) will occur at 3.05am on September 17. Normally, a bright moon will be on full view at night during the Festival period if weather permits. This year, a penumbral lunar eclipse will occur around the time of the Mid-Autumn full moon, which happened once in the past 20 years. The astronomical event will last for four hours and three minutes. As the moon will pass through the penumbra (partial shadow) of the Earth without entering the umbra (total shadow), the moon will become only slightly dimmer during the event. Details are set out in the figure below.

To assist moon-watching by the public, the times of moonrise, transit, moonset, full moon and penumbral lunar eclipse during the Mid- Autumn Festival period are listed in the table below. At transit, the moon passes the local meridian due south and its elevation is the highest of the night.

The previous lunar eclipse at the Mid-Autumn full moon visible in Hong Kong was a total lunar eclipse on September 17, 1997. The next lunar eclipse at the Mid-Autumn full moon will be a partial lunar eclipse on September 29, 2042.

For the moon phase information and the latest weather conditions during the Mid-Autumn Festival period, please refer to the Weather Information for Astronomical Observation webpage (www.hko.gov.hk/gts/astronomy/astro_portal.html) and the

9-day Weather Forecast issued by the Hong Kong Observatory (www.hko.gov.hk/wxinfo/currwx/fnd.htm) respectively for the planning of moon-watching activities.

Please refer to the Observatory's website for a detailed explanation of lunar eclipse and past lunar eclipse events in Hong Kong:

www.hko.gov.hk/gts/event/event-lunar-eclps1_e.htm

Note: At full moon, the Moon as seen from the Earth is completely illuminated with the Moon and the Sun located on the opposite sides of the Earth.