On 27th July, a total lunar eclipse occurred. This was be the second of its kind to grace the skies in 2018. This time, the Moon turning ‘blood’ red was visible from Western Africa, and Central Asia, seen rising over South America, Eastern Africa, and Europe, and setting over Eastern Asia, and Australia.
During this event, the full Moon passed through the Earth’s shadow (or umbra) lasting around 6 hours and 14 minutes from beginning to end making it the longest eclipse this century. The illustration below shows how the Moon passed through the upper portion of the Earth’s central shadow. This meant that the eclipse appeared very dark compared to other lunar eclipses. However there are more factors at play here (read more below).
What did the eclipse look on 27th July 2018?
The Moon slowly turned from its familiar pearly white colour to a reddish colour then back to its original colour all over a period of around six 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 block more of the Sun’s light from refracting around the Earth causing deep, dark red effects. The total lunar eclipse on 28 September, 2015 was considered particularly dark and this was not just down to volcanic eruptions or air pollution. The 2015, the event occurred during a perigee Moon when the Moon is closest to the Earth (coining the phrase ‘Supermoon Eclipse’ at the time). This meant that the Moon was deeper in to the Earth’s umbral shadow. The event on 27th July was the opposite occured during an apogee Moon, however the Moon crossed deeper in to the Earth’s shadow this time around. That being said, it’s hard to predict with certainty how red the Moon will appear during these eclipses. It’s always best to wait and see and enjoy any surprises that these most easily observed astronomical events may reveal.
A photographic opportunity
During totality, many more stars can be seen than what could be seen during the full Moon. It’s a good photographic opportunity for a rare wide field shot of the eclipsed moon complimented by a background of stars. This particular eclipse occurred during moonrise for much of Europe so many could look for a nice landscape picture with an eclipsed Moon backdrop.