Category Archives: astronomy

Heavens above, it’s a solar eclipse!

You may have heard that tomorrow (Friday 20th March 2015) there will be a solar eclipse.  Here in mainland UK it will only be partial, but a large percentage of the Sun will be covered by the Moon so it will be worth having a look at.  Mid-eclipse, when the largest part of the Sun will be covered by the Moon, is about 9.30am.  I will be at St John’s Primary School in Macclesfield in the morning where I will be talking to the school assembly about the eclipse, and hopefully showing everyone the view.

There has, sadly, been a lot of mis-information flying around about viewing the eclipse, and some schools have actually banned their pupils from watching it.  There are many perfectly safe ways to view it, so don’t believe the scare-mongering.

But: never look at the Sun through any kind of telescope, or binoculars, or any other kind of glass instrument!  There are some telescopes designed for safe solar viewing but, unless you really know what you are doing, don’t try it.  You WILL damage your eyesight.  For the transit of Venus in 2004, Stuart and I made a video showing what happens to a simulated eyeball.  It’s not pleasant.

So, how can you watch the eclipse safely?  The simplest and cheapest way, and what I will be doing at school tomorrow, is using a pinhole viewer.  You take a piece of card or stiff paper and make some small holes with a pen.  Hold this between the Sun and another sheet of white paper (or a wall) and voila, small images of the Sun!

How to watch the eclipse

Lots of images of the Sun, formed using a pinhole viewer; the safest way to watch a solar eclipse.

If the weather is good where you are, go have a look.  Look up the exact timings for your location, read the answers to some frequently-asked questions about the eclipse, watch Dr Lucie Green explain the eclipse and how to view it, or read a booklet about the eclipse produced by the RAS.  Good luck!

Quadrantid meteor shower

January 4th sees the peak of the annual Quadrantid meteor shower.  The Quadrantids is often a poorly-observed event due to the weather in the northern hemisphere at this time of year, and 2015 is worse than usual as the peak of the shower coincides with the date of the full Moon.  Caused by the Earth passing through streams of leftover debris from comets or asteroids, meteors showers are conventionally named after the constellation from which they appear to radiate.  The Quadrantids, however, are named after an abandoned constellation named Quadrans Muralis, the mural quadrant, now a part of Boötes, the Herdsman.  Boötes is home to the star Arcturus, a giant star and the fourth brightest star in the sky, although the rest of the stars in the constellation are much fainter.  The radiant of the Quadrantids is located in the north of the constellation, close to the tail of Ursa Major, the Great Bear (see the image below).

Visible only at northern latitudes, the shower is active between December 28th and January 12th, although with relatively low numbers either side of the peak on January 4th.  At the peak of the shower, early in the morning of January 4th, models predict that there will be up to 120 meteors per hour when observing under ideal conditions.  In practice, the numbers observed will generally be lower than the predicted rate (also known as the ZHR, Zenith Hourly Rate) because observing condition are rarely ideal.  Despite being one of the more active showers of the year, the debris which forms the Quadrantids results in meteors which are fainter on average than many of the more well-known showers and, with the first full Moon of 2015 occurring on January 5th, conditions this year are far from ideal for visual observing.  This shower is unusual in that the parent body, the comet or asteroid which left the debris which gives us this particular light show, remained somewhat uncertain for many years, despite the high activity of the shower.  There is more than one candidate object, with many specialists arguing that the asteroid 2003 EH1 is the likely source, but there are other candidates, and the evolution of the orbit makes identification more difficult.

The Quadrantid radiant

The approximate position of the radiant of the Quadrantid meteor shower (image made with stellarium)

My view: this year I saw a big fat zero.  Last night was also the annual visit to Macclesfield Astronomical Society of the historian of science Dr Allan Chapman; the subject of his lecture this year was the astronomer and mathematician Kepler.  Driving home in thick fog at 10:30pm, I gave up plans to do any observing as I could barely even make out the location of the Moon.  Another excellent reason to fix up another radio receiver to replace the now non-functional Jodrell Bank Observatory Meteor Detector

For more information on meteor showers and advice on observing them, visit the International Meteor Organisation.


I’m a compulsive communicator, I can’t help it.  Having suffered from almost paralysing stage fright in my school days, I now jump at any opportunity to stand in front of a public audience and talk about science.  So when an email appeared recently asking for volunteers to speak at SciBArs (science, in the pub, for interested non-experts), I offered straight away.  I contacted Lorelly Wilson of the North-West branch of the British Science Association, describing my current public talk on my research looking at colliding galaxies, and she passed on the details.  I virtually had my hand bitten off, with three bookings within the space of a few hours!

So it was that on Monday September 1st, just three days after my initial email, I found myself at the Knutsford SciBAr presenting my talk “When Galaxies Collide!” to a diverse audience of interested people.  The evening went rather well, with lots of intelligent questions asked by the audience.  Judging from the feedback I received afterwards, the audience thoroughly enjoyed my performance.  Rather unexpectedly, one of the attendees turned out to be a physics professor from Manchester University who taught me back in my undergraduate days!

This week I travelled in the opposite direction and on September 9th I gave the same presentation to the Congleton SciBAr at the Young Pretender Beer Parlour.  Another great audience, with good food and a rather nice selection of beers, resulted in another very enjoyable evening.  As well as taking questions during the performance, I ended up talking to many members of the audience afterwards on topics ranging from black holes, aliens, the fate of the universe, how radio interferometers work, giving advice to an undergraduate physics student, talking about the history of the Observatory, and tree surgery.  Luckily there were plenty of white-backed beer mats to hand, so by the end of the evening the table was covered in science-y scribbles.

It has taken years and a lot of practise, but I’ve found ways of dealing with that stage fright.  It still amazes me when people talk to me afterwards and comment on my confident presentation style, but it shows how far I’ve developed, and public events like these have played a huge part in that process.

If you fancy hearing about what happens when galaxies collide, and seeing how this affects our own future, I’ll be giving the same talk next month at the Didsbury SciBAr, and then Macclesfield SciBAr early next year.

Pimms, finger food, and tales of the end of the world

Sounds like a recipe for a good evening, doesn’t it?  That was the menu on offer at the Shropshire Astronomical Society summer social held in Rodington yesterday evening.  I was invited to be the guest speaker at this event, so after lunch I jumped on a train down to Wellington where I met Mandy Bailey, a fellow SPA Council member and one of the officers of Shropshire Astronomical Society, who gave me a lift to the village hall in Rodington (not far from Knockin, the site of one of the e-MERLIN telescopes).

Now, visits to astronomical societies vary; some take you out for dinner, some go to the pub afterwards, some do neither.  This particular evening started with a bring-and-share buffet and a refreshing glass of Pimms – I was most impressed!  Once people had eaten and the mountain of food had diminished somewhat, we formed teams for an astronomical “Quizz” (the extra “z” for redshift perhaps?).  Our team, the Scatterbrains, came close to being disqualified as we had two PhDs at the table, but I did point out that most professional astronomers have pathetically bad sky-knowledge.  With questions ranging from classical composers to energy calculations to song lyrics, I don’t think we actually had much of an advantage!

Following the quiz and the answers, it was time for my talk.  Starting with a brief look at what a galaxy actually is, we moved on to look at a simulation of what happens when they collide (greatly speeded up of course, as the process takes millions of years – and research contracts are generally only three years long!).  We then used M31 as a case study to see the reasons why we use different parts of the electromagnetic spectrum for probing different aspects of galaxies, with a brief detour into how radio interferometry works and why it is such a powerful technique.  We then looked at a series of examples of galactic collisions in various stages of their interactions, including the results of several ongoing studies being carried out by me and my various collaborators.  We ended with a look at what relevance this all has for the future of our own Galaxy, and a note that the timescales are such that there’s no need to start building a rocket in your shed just yet.

Questions from the audience followed, of which there were several good ones, showing that they had certainly been paying attention!  Sadly I had to leave almost as soon as I was finished in order to catch a train home, but not before they presented me with some cider and a lovely box of chocolates, and a Shropshire AS mouse mat with a picture of the Lovell telescope!  The members of the society (the only one of its kind in Shropshire, I learned) are a very friendly bunch and the evening was thoroughly enjoyable.  After torrential rain for most of the morning, and more showers just after I arrived, the sky did clear up during the evening, promising some good observing from the village hall where the sky is reasonably dark.  I wouldn’t be surprised if some people had a very late night!

Shropshire Astronomical Society: friendly members, good food, great venue.  5 stars!

Going over galaxies with a fine-toothed comb

Last week I gave the July lecture at Macclesfield Astronomical Society at the village hall in Goostrey.  I’ve been a member of the society since I was eleven, and it still feels strange to be giving lectures there, rather than listening to other people speak!  The talk I gave on Tuesday is one I wrote some time ago, so it needed some updating to reflect the current state-of-the-art, and a bit more in the way of introductory material to make it a full-length public lecture.  The feedback I’ve had suggests that I pitched it about right, which is always reassuring!

The title of the lecture is “Going over galaxies with a fine-toothed comb”, and describes the current efforts to map nearby galaxies in astonishing detail using a technique called wide-field very long baseline interferometry – a bit of a mouthful however you look at it.  There’s a brief description over on my talks page, but if you want the full story then you’ll just have to book me for an event!

After the lecture someone asked how I manage to remember the whole script for a talk like that.  It got me thinking about how my lectures have developed over the years.  When I started doing outreach and public talks (over ten years ago now) I was exceedingly nervous and would write a script to help me remember everything I wanted to say.  As I quickly discovered, the trouble with a script is: 1) it’s tempting to read from it, which is very boring for the audience, and 2) you still forget to say things, and then get flustered when you lose your place!  So, now I don’t use a script, and I haven’t done for a long time.

The next logical question is then, how do I remember what I’m going to say?  Simple: I don’t.  I design my slides so that they tell a story in pictures.  Then all I have to do is tell the story as I step through the pictures.  The advantage of this is that I don’t need to practise – if I have to give a talk I haven’t done for years, I can just stand up and give it, without having to re-learn a script first.  I find it makes my talks more spontaneous and, hopefully, more engaging for the audience.

I have a few more bookings this year, at astronomy societies, an SPA weekend event for beginners, and he odd public SciBar, so if you would like to come and hear some of my stories head over to my events page.

New blog – finally.

It’s taken me a while to get around to it, but I finally installed wordpress on here.  Not that the old marzipan software wasn’t pretty good, but the ridiculous amount of comment spam it was getting did start causing problems.  So, new blog!

The first post is a quick advert for tonight’s lecture: I’m speaking at Macclesfield Astronomical Society, about how we are now able to map areas the size of the full Moon at milli-arcsecond resolution.  (Now that wont mean a lot to most people so, to put it in context, that’s about 50 times sharper than the Hubble Space Telescope!)  This relatively new technique has opened up the sky to high-resolution surveys at radio frequencies, allowing us to probe nearby galaxies in exquisite detail, and to investigate large populations of much more distant objects.  Right now, this technique generally requires special software, large amounts of disk space, and plenty of processing time, but as computers get ever more powerful and we look towards the Square Kilometre Array with great anticipation, these techniques will become more and more commonplace.  It’s an exciting time to be in radio astronomy.