A guide to astronomy with 2020 Stargazing authors Nigel Henbest and Heather Couper
An interview with the authors of 2020 Stargazing, in which they discuss their time in Cambridge, their favourite sights in the night sky, the highlights for 2020 and what telescope to buy.
Gaze up to the night sky on one special day next year, and you’ll see an extraordinary sight.
Jupiter, the largest planet in our solar system, and Saturn, arguably the most striking, will appear closer together than they have for nearly 400 years.
“They will almost look as if they merged into one brilliant star,” says Nigel Henbest, co-author of the new book, 2020 Stargazing.
“If you look through a small telescope you’ll see in the eyepiece, at the same time, Jupiter with its moons and Saturn with its rings. So fingers crossed for a clear night on December 21, 2020.”
Written with Nigel’s long-term collaborator and friend Heather Couper, the book is a month-by-month guide to what to look out for in the night sky.
It is the 16th of these annual guides written by the prolific pair, who have clocked up 50 astronomy books between them.
Their partnership was forged at Leicester University, where they met while studying astrophysics, but both have fond memories of their very different experiences at Cambridge.
Heather came to the city after a spell working as a management trainee at Topshop.
“I came second in my exams but I was getting bored. I went to the library one day in Ruislip and remembered that as a kid I’d been really interested in astronomy, so I wandered across to the astronomy books and found a factual book by Isaac Asimov called Universe.
“I read it cover to cover and thought, ‘I’ve got to get back into astronomy’.
“I went to an amateur conference and met someone who worked at the Institute of Astronomy in Cambridge who said there was a little job. I got in with my dreadful qualifications – only two A-levels – and was measuring data.
“Everyone at Cambridge said there was no future unless I got an extra A-level so I would cycle to Cambridge Tech on Monday evenings. It was ghastly – I hated Mill Road!
“I studied maths and scraped through with the lowest grade, but it was enough to get me into Leicester, where I met Nigel.
“But my recollections of Cambridge were amazing. Suddenly I was in a place where everybody seemed to be under the age of 25 and they were all questioning. It was very exciting. I did love Cambridge.”
While Heather went on to study at Oxford, Nigel came to Cambridge, and St John’s College, for his postgraduate research.
“I wanted to research at the cutting edge of astronomy. The Cavendish Lab had Sir Martin Ryle, the Astronomer Royal, and he had just built the Ryle Telescope.
“That was the most powerful telescope of its kind in the world. We put smaller dishes in a long line, so it was effectively a telescope three miles or five kilometres long.
“I was one of the first researchers to be working with that.”
It was in 1972-73 that Nigel used the Ryle Telescope to make pioneering observations of the remnant of Tycho’s supernova, the remains of a star that blew itself apart.
It was named after the person who observed it in 1572 – Danish aristocrat Tycho Brahe, a man also famous for wearing a prosthetic metal nose after losing his in a sword duel.
“Although it is thousands of light years away, the light was so brilliant, it was the brightest thing in the sky. Four hundred years on we were picking up radio waves from this exploding star,” recalls Nigel.
“Then we turned the Ryle Telescope onto quasars, or exploding galaxies, which are among the most distant objects. They can be at the edge of the universe but they are so bright they can be seen in a backyard telescope. In a radio telescope, they are really powerful things to look at.
“What we didn’t know then, but do know now, is that what is responsible is a black hole at the centre of these galaxies, which is super massive, as heavy as billions of suns condensed down. Its gravity rips up stars as it goes around, which creates all the energy that we were picking up.”
Since 1978, the pair have been helping to popularise astronomy, through books, TV and radio programmes, and talks.
“When you go outside on a beautiful night, you see the beauty of the skies, just as you see the beauty of a landscape,” says Heather.
“Astronomy is art as much as it is science, and that’s something we try to bring out in all of our books. Many of them have been tied up in TV programmes.”
Heather, who has appeared on the BBC’s The Sky at Night, presented the prime-time series The Planets for Channel 4, followed by The Stars, and profiled Cambridge own’s Prof Stephen Hawking for BBC4. Together the pair presented Seeing Stars on the BBC World Service from 1989 to 2001.
“We go around the world and give presentations – we’ve been everywhere, including Japan, China, America, New Zealand and Colombia,” says Heather.
“We set up a big TV company. It became a very big company, earning millions of pounds, which was rather nice. I got myself an indoor pool. Nigel got himself a ticket into space,” says Heather, alluding to her co-author signing up in 2009 with Virgin Galactic for a potential future suborbital flight into space on SpaceShipTwo, from Spaceport America, the world’s first commercial spaceport.
“The point is, astronomy is for everybody, not just for geeks,” adds Heather.
And the pair’s latest book, published by Philip’s, is designed with this in mind.
“Each month starts with a map – a chart of the whole sky – to show you where everything is, then there’s a diary of what’s happening day-by-day and a more detailed look at where the planets are,” says Nigel.
“I was brought up in the 1960s on the monthly guides available then. But they were so boring... you needed a lot of technical background even to understand them.
“So we went into this to be user-friendly, and think about the reader. We do a little bit of jargon, like magnitudes for how bright stars are, but we explain all that up front.”
From meteor showers and comets, to the movement of the planets and special sights to look out for, the guide is designed to help us connect – or perhaps reconnect – with the night sky.
“Centuries ago, before light pollution, the skyscape was as important as the landscape,” Nigel points out. “If you look at Shakespeare, there are many references to the stars. People knew them – it’s part of our culture. Often I will go out and lie on my back and look up the skies.”
With a copy of 2020 Stargazing, you’ll be well placed to understand what you’re looking at if you follow suit.
Highlights of 2020
Jupiter and Saturn appear close together on December 21
Nigel’s top highlight of next year comes towards the end of the year, when these two gas giants will appear right next to each other.
“Over this summer, you’ve probably seen Jupiter looking brilliant in the south and Saturn relatively nearby. They are beginning to sink down into the west. Next spring they will come back again. They are getting closer and closer,” he says.
Enjoy the Geminids meteor shower on December 13-14
Heather’s top highlight comes a week earlier.
“We have various meteor showers during the year, when the Earth ploughs through debris left by decaying comets. These are tiny - about the size of coffee grains - that burn up in the atmosphere about 100km up. There is usually a very good one in August - the Perseids - but it’s often spoilt by the moon, which is the case this year.
“But on December 13-14 you should see the Geminids, which are made of very heavy particles, that are usually very bright. This one won’t be spoiled by the moon.
“We should be in for a storm of really serious meteors, which I’m looking forward to.”
The planets in 2020
See Mars looking brilliant in October
“Mars come close to the Earth every two years,” says Nigel. “In October it will be one of the brightest things in the sky, after the moon and Venus. It will be brighter than Jupiter.
“A whole flotilla of space probes are being sent to Mars, like the American follow-up to their Curiosity rover, which has been on Mars for seven years. Even more importantly is Exo-Mars, a European and Russsian mission which will land a rover on the surface. It’s named Rosalind Franklin after the British chemist involved in the discovery of the structure of DNA.
“That has British experiments on board looking for extant life, as befits her name.
Find tricky Mercury
Often impossible to see, because of its proximity to the sun, Mercury will be visible in the evening in February or, if you’re up before dawn, in November.
“The key thing is you need a low horizon, so no trees or houses in the foreground. As it sets, it appears near the horizon,” says Nigel.
Let Venus guide you to Neptune, the outermost planet
“Venus early in the year will be an evening ‘star’, looking brilliant in the west. Most people can find it, because it’s brightest thing in the sky after the moon,” says Nigel.
“If you have a telescope and look near it, you’ll find Neptune. Neptune is also visible in binoculars, but is quite faint.”
Let Mars guide you to the dwarf planet, Pluto
“Mars is going to be really close to Pluto in March,” says Nigel. “You need a six-inch telescope to see Pluto. It’s an amazing thing on March 23 - Pluto is almost exactly behind Mars. Because Mars relatively quickly across the sky, it literally could be that morning only.
“I love it when a bright planet is a signpost - Venus shows us Neptune, then Mars shows us Pluto.”
Spot Uranus at Hallowe’en
“Uranus is at opposition - when it’s highest and brightest - on October 31,” says Nigel. “Uranus is just visible to the naked eye. Before it was recognised as a planet, it was sighted and put down as a faint star. It’s easily seen in binoculars.”
Glimpse other galaxies
“The best time to see galaxies is spring,” says Heather. “Then, you can see the constellation of Leo, which looks like a recumbent lion, with his head and body. Next to it is Virgo, which looks like a big Y shape in the sky. All you need to do is see galaxies is a pair of binoculars, and you can sweep inside the shape of the Y. You’ll see some of the 2,000 galaxies that make up the enormous Virgo cluster.”
Nigel adds: “At the other end of the year you can see the Andromeda galaxy.”
Nigel and Heather’s favourite sights in the night sky
“For me, it has to be Saturn,” says Nigel. “I remember first seeing Saturn through my telescope. It’s so sharp and crystal clear and it looks so other-worldly. Saturn looks like a little model hanging at the end of the telescope. It looks three-dimensional, which not many things in space do.”
Heather adds: “I’d go for the Andromeda Galaxy. It’s visible with the naked eye, but giving it more oomph - with binoculars or a telescope - fills in more detail of its glorious spiral arms. You marvel at the size of the beast. It’s bigger than our galaxy, it has more stars.
“The universe is populated with these. This is one of our nearest, and I love it.
“It’s a stepping stone to billions of other galaxies in the universe, and it makes you aware of the breathtaking scale of our universe.”
Nigel and Heather on equipment...
“Start with the naked eye. Don’t buy a telescope before you’re initiated - it’s like looking through a loo tube!” says Heather.
“I got to know my sky by holding a planisphere and matching it to the stars over my head.
“You’re then ready to turn to a pair of binoculars.”
Nigel adds: “Today, there are some very good apps, which can tell you where the planets and constellations are, but they don’t give you the big picture. So get a book with monthly star charts... Learn your way around the constellations.
“It tells you in our books what the legends are - Hercules and his labours, why there’s a lion in the sky, why Orion is there with his two faithful dogs.”
Once you’ve familiarised yourself with the night sky, and want to take your interest further, then it’s time for a telescope.
“You need to take some very good advice,” says Heather.
“Prices of good telescopes have come down hugely. By and large you get what you pay for, but you have to start with budget. What do you want to spend?”
Which telescope should I get?
There are three principal types of telescope:
Refractors: the classic and earliest type of optical telescope, around since the days of Galileo in the early 17th century. A convex lens at the front bends or refracts the light, so it converges at a focal point. The user sees the image magnified through the eyepiece lens, at the end of the telescope. Easy to use for beginners, refractors are good for viewing the moon and planets.
Reflectors: invented by Sir Isaac Newton in the 17th century as an alternative to the refractor telescope, reflectors use concave mirrors to reflect the light and display the image. Widely used to observe the moon, planets and deep sky objects, with reflectors you look through the side of the tube.
Catadioptric telescope: using lenses and mirrors, these hybrids effectively combine features from refractors and reflectors.They are smaller, and more portable, but can be more expensive. There are a number of types, such as Schmidt-Cassegrain telescopes.
Price, size and your intended targets are all factors in picking one of these.
Those seeking deep space objects as well as planets and the moon may favour a reflector.
But Heather notes that they may be more tricky to use for beginners.
“My first telescope was a refractor. It is more intuitive to be looking along the line of where it’s pointing. In reflectors, you look through the side of the tube, which is counter-intuitive for a beginner,” she says.
But the scope is only half of the matter. The mount on which the scope is placed is equally important.
Alt-azimuth, or alt-az, mounts are simple two-axis mounts, which allow you simply to move up/down or horizontally, like a simple camera tripod.
Equatorial mounts are more complex in their motion because they mimic the motion of stars as seen from Earth, allowing their movement to be tracked. This is particularly beneficial for those looking to get into astrophotography.
Another option is a Dobsonian - a type of alt-az reflector telescope design, which uses a box-type mounting, allowing the telescope to pivot, while the box rotates. These offer good value, and enabling you to have a larger scope for deep sky viewing. But they’re not suited to astrophotography.
Nigel advises: “If you have a little bit more money, go for a computerised mounting. You can end up paying as much for the mount as the telescope. If you have the ‘Go-To’ controls, you can ask it to go to Jupiter and it will go around and found Jupiter.
“The downside is it’s like using sat-nav. You can go straight to Jupiter but you won’t understand where it is in the sky, or how it relates to the constellations.”
2020 Stargazing is out now, published by Philip's, and priced £6.99.