The Sky at Night: Astronomer, Dr Affelia Wibisono

July is a very eventful month with plenty to see in the night sky. The standout astronomical event of the month is the total lunar eclipse which occurs on July 27.

Dr Affelia Wibisono – Astronomer at the Royal Observatory, Greenwich

During this time, the sun, earth and moon are in alignment with the earth in between.

Totality starts when the moon enters the centre of the earth’s shadow, called the umbra.

Unfortunately, for UK observers, the moon will already be in the earth’s umbra when it rises at 8.50pm and it will already appear red.

However, it will take almost an hour-and-a-half for it to pass through the umbra and so will retain its reddish hue until around 10.15pm.

As our celestial neighbour leaves the edge of the earth’s shadow, it will look slightly darker when compared to a normal full moon.  Look towards the south-east to see the lunar eclipse.

Try to find an open area on top of a hill with a clear view of the horizon as the moon will be quite low in the sky.

Lunar eclipses are completely safe to look at so you won’t need eye protection when viewing it.

Planet hunters will be spoilt for choice in July as three bright naked eye planets are visible at sunset throughout the month.

The brightest of the three is Venus which will appear fairly low in the western sky.

However, its position in the sky will get lower and lower with each day, making it more and more difficult to spot in areas with an obscured westerly horizon.

Jupiter and Saturn can be found towards the southern sky and will remain in the sky long after the sun sets.

Those who are willing to wait until the small hours will also be able to witness a fourth naked eye planet.
Mars will be visible from around 1am at the beginning of the month, but by the end of July, Mars will rise earlier in the evening which means that it will be visible from around 11pm.

Coincidently, Mars will be at opposition on the night of the lunar eclipse.

Planets are said to be at opposition when they are on opposite sides of the sky from the earth’s point of view.

It is often said that the best time to observe a planet is when they are at opposition because this is when they appear to be at their largest and brightest as it is when they are at their closest.

Do not worry if the night turns out to be a wash out – Mars will still look magnificent for many months.

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