It's a rare spectacle sure to delight sky-watchers.

Eastern Daily Press: A blood moon seen at Gorleston in 2015 Picture: Wayne DaveyA blood moon seen at Gorleston in 2015 Picture: Wayne Davey (Image: (c) copyright citizenside.com)

The night of January 20/21 will see a so-called blood moon.

The phenomenon, which usually occurs just twice in every three years, is caused by a lunar eclipse, where the earth's shadow prevents light from the sun from reaching our nearest celestial neighbour.

Sunlight scatters through the earth's atmosphere as the three bodies perfectly align, making the moon appear red.

The spectacular event should be visible from Norfolk - provided the skies are clear enough to see the moon.

Eastern Daily Press: A 'blue blood moon' sets over Beccles.Picture: Nick ButcherA 'blue blood moon' sets over Beccles.Picture: Nick Butcher (Image: Archant © 2018)

But the bad news for would-be lunar eclipse watchers is the timing. For the skies over our region are not expected to turn red until after 4am on the morning of Monday, January 21.