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Partial lunar eclipse on 1 January
(18 December 2009)

A partial eclipse of the moon will occur on 1 January (Friday). In Hong Kong, even with good weather conditions, people will only see the moon darkened with just a small part eclipsed owing to the small magnitude of the eclipse.

The lunar eclipse will occur between 1.15am and 5.30am with maximum eclipse at 3.23am. The eclipse has an umbral magnitude of just 0.082, meaning that only 8.2% of the moon's diameter will enter the umbra (total shadow) of the earth at maximum eclipse. Please refer to the attached diagram for the path of the moon during the eclipse.

Details of the partial lunar eclipse are as follows:


 Hong Kong Time



 Moon enters penumbra



77 degrees

 Moon enters umbra



56 degrees

 Maximum eclipse



49 degrees

 Moon leaves umbra



42 degrees

 Moon leaves penumbra



22 degrees

The next lunar eclipse visible in Hong Kong will occur on 26 June, 2010. It will be more observable with a magnitude of 0.542.

Please refer to the Observatory's website for a detailed explanation of the technical terms used for different stages of the eclipse:

Diagram: Partial eclipse of the moon on 1 January 2010
Diagram: Partial eclipse of the moon on 1 January 2010



Last revision date: <21 Dec 2012>