The night sky during July

The total lunar eclipse of June 15 was one of the longest in recent years. It was also one of the darkest. This may have been partly due to increased aerosol content in the upper atmosphere resulting from the eruption of the Puyehue volcano in Chile.

Even during totality, a sombre, red lunar disc could be seen in the starry night sky, reflecting reddened light falling on to its surface. Seen from a lunar perspective, the ruddy illumination is from all the sunsets and sunrises around the edges of a silhouetted Earth.

In this sharp portrait of the eclipsed moon by Leonard Ellul Mercer, the moon appears totally red as it delves deep into the Earth’s shadow.

On some occasions the moon’s edge reflects a bluish tinge as well as it emerges from Earth’s umbral shadow. The bluer light is still filtered through Earth’s atmosphere, but originates in rays of sunlight passing through layers high in the upper stratosphere.

That light is coloured by ozone that absorbs red light and transmits bluer hues.

Astronomical events during July

Mr Pace is vice-president of the Astronomical Society of Malta.

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