On the night of July 16 & 17, 2019 a partial lunar eclipse will occur. During this eclipse, a good portion of the Moon will turn ‘blood’ red visible in the evening skies on the 16th from south America, Africa, Europe and western Asia. The eclipse will also be visible in the early hours of 17th July from eastern Asia and Oceania/Australasia just before moonset.
During this event, the full Moon will pass through the Earth’s shadow (or umbra) lasting around 5 hours and 37 minutes from beginning to end. The illustration below shows how around 65% of the Moon will pass through the Earth’s central shadow. This means that our natural satellite will not appear as dark as the last two lunar eclipses in January 2019 and July 2018 which were total. However, this is still an event worth staying up to watch.
How will the eclipse look on July 16, 2019?
The Moon will slowly turn from its familiar pearly white colour to a grey-reddish colour (with the red tinge appearing toward the top half of the Moon) then back to its original colour all over a period of around five and a half hours.
The shade of red can vary from eclipse to eclipse depending on a few factors including conditions in the Earth’s upper atmosphere and the position of the Moon along its orbit. If there have been any significant volcanic eruptions for example, this can cause the Moon to appear a much darker red than of other eclipses. The added amount of volcanic ash and dust in the Earth’s atmosphere can prevent more of the Sun’s light from refracting around the Earth causing deep, dark red effects. The total lunar eclipse on 27 July 2018 was considered particularly dark. This eclipse being only partial, all these effects will be less prominent and the Moon overall will appear much brighter during this partial lunar eclipse.