Written In The Stars
Things are looking up
A new edition of the Month-By-Month Guide to the Night Sky from astronomy writers and broadcasters Professor Nigel Henbest and the late Professor Heather Couper has been released (out September 3). Covering the skies over Ireland and Britain, Philip’s Stargazing 2021 is a practical guide for budding and experienced astronomers.
About the authors
Professor Heather Couper was President of the British Astronomical Association, a Fellow of the Institute of Physics and a Fellow of the Royal Astronomical Society. She was awarded the CBE in 2007 for Services to Science. Heather sadly passed away in February 2020, while writing Stargazing 2021.
After researching at Cambridge, Professor Nigel Henbest became consultant to both New Scientist magazine and the Royal Greenwich Observatory. He is a future astronaut with Virgin Galactic. 2020 has shaped up to be a year like no other, so why not channel your inner star-gazer to look up and ahead with this practical guide to the most fascinating events the solar system has in store for 2021
Can you see the planets? We’re amazed when people ask us that question. Some of our cosmic neighbours are the brightest objects in the night sky after the Moon. As they’re so close, you can watch them getting up to their antics from night to night. And planetary debris - leftovers from the birth of the Solar System - can light up our skies as glowing comets and the celestial fireworks of a meteor shower. THE SUN-HUGGERS
Mercury and Venus orbit the Sun more closely than our own planet, so they never seem to stray far from our local star. You can spot them in the west after sunset, or the east before dawn, but never all night long.
Through a telescope, Mercury and Venus (technically known as the inferior planets) show phases like the Moon - from a thin crescent to a full globe - as they orbit the Sun.
Mercury
The innermost planet appears in the evening sky in January, makes its best appearance in April - May, and then reappears in the dusk sky during last few days of the year (its evening appearance in August - September is largely lost in the bright twilight). Mercury is low in the dawn twilight at its February - March and July apparitions; it’s best seen before dawn in October - November.
Venus
Though you’ll catch Venus in the morning sky in January, it lurks behind the Sun through to the middle of April. From then till the end of the year, Venus is a permanent fixture of the western dusk twilight in the evening sky, as the Evening Star. It reaches its greatest separation from the Sun in October, and maximum brightness on December 7.
WORLDS BEYOND
A planet orbiting the Sun beyond the Earth (known in the jargon as a superior planet) is visible at all times of night, as we look outwards into the Solar System.
It lies due south at midnight when the Sun, the Earth and the planet are all in line - a time known as opposition.
Around this time the Earth lies nearest to the planet, although the date of closest approach (and the planet’s maximum brightness) may differ by a few days because the planets’ orbits are not circular.
Mars
The Red Planet hangs around in the evening sky for most of the year, gradually fading as its distance from the Earth increases. Disappearing from the evening sky in August, and passing behind the Sun on October 8, Mars reappears in the dawn twilight in November.
Jupiter
The giant planet starts the year low in the evening sky, sinking into the sunset by the end of January. It reappears in the morning sky at the end of February, still in Capricornus where it remains until May
SOLAR ECLIPSES
when Jupiter moves into Aquarius. Reaching opposition on August 20, Jupiter moves back into Capricornus in September, and is visible in the evening sky until the end of the year, when it treks into Aquarius again.
You’ll find the ringed planet near Jupiter throughout the year. In January, it disappears into the twilight glow, to re-emerge at the end of February in the dawn sky. Saturn is at opposition on August 2, and you’ll then see it in the evening sky until the close of 2021. It resides in Capricornus all year.
Uranus
Just perceptible to the naked eye, Uranus lies in Aries all year. Up until May, the seventh planet is visible in the evening sky. It emerges from the Sun’s glow in the morning sky in July. Uranus is at opposition on November 5.
Neptune
The most distant planet lies in Aquarius throughout the year, and is at opposition on September 14. Neptune can be seen (though only through binoculars or a telescope) in January and February and then from late April until the end of the year.
On June 10, anyone who’s in a narrow strip of the Earth’s surface - from north-east Canada via the North Pole to eastern Siberia - will be treated to an annular eclipse of the Sun.
Ireland and Britain will experience a partial solar eclipse - from the south-east of England, the Moon covers 19 per cent of the Sun, rising to 35 per cent as viewed from Shetland.
On December 4, a total eclipse of the Sun is visible from West Antarctica and adjacent regions of the Southern Ocean. Nothing is visible from Britain.
LUNAR ECLIPSES Saturn
A total lunar eclipse on May 26 will be seen from the Pacific Ocean and the countries of the Pacific
Rim, but not from the British Isles.
On November 19, a large partial eclipse of the Moon is visible from the Americas, the Pacific and eastern Asia. As seen from Britain, the eclipse begins as the Moon is setting.
Where the dark central part (the umbra) of the Moon’s shadow reaches the Earth, we are treated to a total solar eclipse. If the shadow doesn’t quite reach the ground, we see an annular eclipse. People located within the penumbra observe a partial eclipse.
METEOR SHOWERS
Shooting stars, or meteors, are tiny specks of interplanetary dust, burning up in the Earth’s atmosphere.
At certain times of year, Earth passes through a stream of debris (usually left by a comet) and we see a meteor shower.
The meteors appear to emanate from a point in the sky known as the radiant. Most showers are known by the constellation in which the radiant lies.
It’s fun and rewarding to hold a meteor party.
Note the location, cloud cover, the time and brightness of each meteor and its direction through the stars – along with any persistent afterglow (train).