The North West Astronomy Festival & Tour of the Universe

Just a quick heads up to say that I’ll be appearing at two exciting events this month. The first, next weekend, is the 2014 North West Astronomy Festival in Runcorn, Cheshire. I’ll be giving a talk on the Saturday (11 October) about the ‘Secrets of Celestial Light’. Here’s the flyer:

You can get tickets to my talk and the rest of the event – and see the full line-up for the weekend, which includes Damian Peach, Helen Keen and Jon Culshaw – at the festival website here. I’ll also be doing a book signing for the Knowledge Observatory on the Saturday afternoon if you’d like to pick up a copy of The Practical Astronomer or The Night Sky Month by Month.

The second event I’m appearing at this month is a theatre-based astronomy chat show called Tour of the Universe. This exciting new touring production is visiting the Nottingham Playhouse on the 20th of October and I’ll be the special guest of presenters Neil and Jane on the night. Tickets to the show can be booked through the Nottingham Playhouse box office or online here.

 

Opening the new Chigwell School observatory & science labs

Last Friday I had the tremendous privilege of opening a new observatory and two new science laboratories at Chigwell School in Essex. The telescope housed within the observatory dome is an 8-inch Meade Schmidt-Cassegrain on a German equatorial mount.

It was wonderful to meet such an engaged and enthusiastic group of students, teachers and staff during my visit, and I’m sure that the school has an exciting astronomical future ahead of it. Many thanks to Steve Davis from Chigwell School for the pictures of the day posted below.

5 Preparing to cut the ribbon. Credit: Steve Davis/Chigwell School

unveiling Officially opening the new science wing of the school. Credit: Steve Davis/Chigwell School

Lab 3 One of the new science labs at the school. Credit: Steve Davis/Chigwell School

lectureGiving a talk about the Mars Science Laboratory mission. Credit: Steve Davis/Chigwell School

Alien worlds at the 2014 International Astronomy Show

Image credit: ESO/L. Calçada/Will Gater

I’m delighted to be speaking at this year’s International Astronomy Show, which is being held at the Warwickshire Exhibition Centre on 7-8 June. I’ll be giving my talk ‘Alien worlds – the extraordinary inhabitants of the Milky Way’ at 10am on the Saturday; in it I explore how we’ve discovered nearly 2000 extrasolar planets in our Galaxy and look to the future and what astronomers hope to find in the coming years. Last year’s show was a huge success and it was great to catch up with old friends and meet many new ones too. If you’re an amateur astronomer in the UK, this is one event you won’t want to miss.

The Gadget Show – astronomy apps and telescope tech

Back in December I spent a fun evening filming with the team from The Gadget Show in the spectacular ruins of Llanthony Priory, in Wales. We filmed a segment for the last episode in series 19, which aired on Monday, about astronomy apps and amateur telescopes. If you’re in the UK and you missed the broadcast you can watch it again by following this link to The Gadget Show video player.

Northern Lights over the UK — 27 February 2014

Last night, following a coronal mass ejection impact, the auroral oval shifted south enough for the Northern Lights to be visible from southern England. Having watched the POES plot get angrier and angrier during the course of the early evening and with the IMF stubbornly south, I decided to jump in my car and drive out of Bristol.

I headed a little way east, to avoid an oncoming cloud front, and found a place to park just northeast of the Bath junction of the M4. As I got out of the car it was clear there was a diffuse glow hugging the northern horizon and every now and then I saw a faint ray appear above it and then dissolve away. No colour was visible to the naked eye though. Thinking (and hoping!) this might be an aurora, and not a trick of the distant light pollution, I set up my DSLR camera and opened the shutter for 20 seconds.

The following images are what I recorded over about ten minutes, after which the sky hazed up considerably and I decided to go home.

Please note that all the images are copyrighted. Clicking on the image will take you to a larger version.

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The asteroid with a surprising tale

With the Geminid meteor shower reaching its peak this weekend – as the Earth passes through the debris trail left by the asteroid Phaethon – here’s an interview I did at EPSC 2013 with Professor David Jewitt about his discovery of the rocky body’s unusual behaviour.

(3200) Phaethon is responsible for the Geminid meteor shower (illustration). Credit: Will Gater

What prompted you to study Phaethon?

We were interested in the Geminid meteoroid stream and where the Geminid meteors come from. When the parent of the Geminid meteors, (3200) Phaethon, was discovered and found to be an asteroid it was interesting to ask why would an asteroid produce dust particles. Phaethon was identified in 1983, but until recently it showed no evidence of any strange behaviour. It just looked like an asteroid, which it is, but it didn’t seem to produce any material or show any obvious mechanism for producing dust. The breakthrough was to use a solar telescope [STEREO] to look at it when it’s near the Sun, when it’s very very hot, instead of using a big night-time telescope when you tend to look away from the Sun. And apparently Phaethon is active when it’s near to the Sun but not far away from it.

Artist’s impression of one of the STEREO spacecraft. Credit: NASA/Goddard Space Flight Center Conceptual Image Lab

So these were relatively recent observations?

Yeah, they were taken with a couple of spacecraft [STEREO A and B] that look at the Sun all the time. Phaethon just happens to pass through their fields of view. It’s been doing that for some years, but we just started to look at the data recently and we found this kind of interesting result. We took the individual images from STEREO and we shifted them and added them together, basically to build up the signal to noise and to make a kind of super image with all of the motion removed. Then we could see the elongation [of the tail] pretty clearly.


And that tail only emerges around the time when Phaethon is close to the Sun?

Yeah, when Phaethon is at its closest to the Sun – 0.14AU, so it’s really close.

Phaethon’s elongated tail appears in the processed STEREO images. Credit: Jewitt, Li, Agarwal/NASA/STEREO


Is the tail material that you’ve detected around Phaethon responsible for the Geminid meteors?

The particles that we see are small and we can tell that because they are pushed very strongly by radiation pressure from the Sun. Radiation pressure is very weak but it can accelerate these dust particles strongly. That’s only possible if they are really tiny, like a thousandth of a millimetre. But the rocks that make the meteors that you can see at night time are more like a millimetre in size so they are individually much bigger than the ones that we see. But on the other hand it’s quite possible, in fact likely, that they are there [in Phaethon’s tail]. You have a distribution of particles sizes – lots and lots of little tiny ones and not so many big ones. The big ones cause the meteors but if you’re just looking at reflected light it comes mostly from the small ones. So we naturally detect the small ones.

So in amongst the small particles you’ve seen there must be bigger ones?

Right, and so the issue is can we go the next step which is to find those bigger guys and prove that those are the Geminid meteoroids being produced now. That would answer the question “is Phaethon still producing the Geminid meteoroids?” Or was there some historical event that was like an impulsive explosion of stuff that came out and that made this ring of debris that the Earth goes through every year. Or is it an active process and this body is continuing to decay.

How can we see those larger particles?

We can’t see them with the solar observing spacecraft, we’ll have to use night time telescopes. We have to see Phaethon in a dark sky and try to see these comparatively rare big particles just by looking very carefully at night time with some big telescope somewhere.

What’s the mechanism releasing the small particles?

We think they’re just being fractured off the surface because the surface is so hot. If you take a rock and heat it up it’s going to expand; a typical rock is made of little grains of different minerals and they’ll all expand at slightly different rates. So if you just heat up a rock it will tend to fracture itself because one part is going to expand more than the other. And when it fractures some of the energy of the expansion goes into the kinetic energy of the fragments. So we think they’re almost like popcorn, bursting on the surface of the object and popping off. And as soon as they leap off the surface then this weak pressure from sunlight can blow them away into a tail.

How long is the tail?

The piece that we see is 350,000km long and it appears in one day. So it goes from nothing to 350,000km in one day. To get up to that speed in such a short time you need a big acceleration. And that’s how we infer the particle size – they have to be small and light to be accelerated quickly to go into the tail.

How hot does Phaethon get when it’s close to the Sun?

At midday on the surface of Phaethon with the Sun directly overhead you have the peak temperature, which is about 1000K [over 700°C]. We know that if you take rocks that we find on the Earth and heat them up to those same temperatures they do crack. Some rocks contain water and they dry out, shrink and crack at temperatures even lower than that.

And that’s hot enough to rule out water-ice helping form the tail?

Yeah. There’s no way to keep water ice at the surface – it sublimates so quickly.

Finally, you’ve also ruled out the tail being a sodium tail. Why’s that?

Well if you look at comets, there are some that go close to the Sun. Some of those comets show a sodium tail. The sodium seems to come from rocks; it is boiled out and gets blown away, making a distinct sodium tail. So I thought maybe that could be the case also for Phaethon. But, in fact, it can’t be because we have a filter on the camera that excludes light from sodium so we couldn’t, even if it were there, see it.

You can read the paper announcing the discovery of Phaethon’s tail here: http://arxiv.org/abs/1306.3741

The Perseids pack a punch thanks to clear skies

The skies were mostly clear in southern England for the peak of the Perseid meteor shower last night. Here are a few pictures that I captured of the display from the countryside to the east of Bristol.

Perseid fireball_12-13 08 2013webA brilliant Perseid fireball streaks across the sky. Credit: Will Gater

fireball_animation_smallThe same fireball image as above animated together with the previous and following frame to show the presence of a ‘persistent train’. Credit: Will Gater

Perseid 12-13 08 2013webA faint Perseid (top right), the Andromeda Galaxy and Double Cluster. Credit: Will Gater

Perseid fireball_dew_12-13 08 2013webA spectacular Perseid fireball captured with a lens covered in dew! Credit: Will Gater

Perseid_12-13 08 2013_croppedA Perseid meteor falls through the constellations of Pegasus & Aquarius. Credit: Will Gater

Sporadic meteor 13082013Not a Perseid! A short sporadic meteor points the way (sort of) to M31. Credit: Will Gater

Summer stargazing on Dartmoor

Despite the short nights, and often poor weather, the summer night skies offer some spectacular celestial sights. My favourite areas to observe at this time of year are the rich swathes of the Milky Way in Cygnus, Sagittarius and Scutum. These regions are packed with dense starfields, glowing emission nebulae and some of the night sky’s finest star clusters.

On Saturday I spent the evening on Dartmoor imaging these wonderful parts of the sky. I wanted to capture a large portion of them in each frame, so I used a 50mm prime lens on my unmodified Canon 550D DSLR, which itself was mounted on an HEQ5 Pro mount.

The first image below shows part of the Sagittarius, Scutum & Serpens region. Several Messier objects are visible in the frame, including: M8 (the Lagoon Nebula), M20 (the Trifid Nebula), M22, M17, M16 (The Eagle Nebula) and M24. The second shot shows a region of the Milky Way in the constellation of Cygnus. The red glow of the North America Nebula (NGC 7000) and the nebulosity around the star Sadr (right of centre) are apparent. You can also, just, make out the two main fragments of the Veil Nebula right on the very bottom edge of the frame. The shot with the silhouetted tree is a single 15-second exposure, at ISO 1600, with the lens wide open at f/1.8.

Dust lanes weave through the Sagittarius, Scutum & Serpens region. Credit: Will Gater

The Milky Way near the bright star Deneb (top) in Cygnus. Credit: Will Gater

A lone Dartmoor tree stands silhouetted against the summer Milky Way. Credit: Will Gater

Envisioning the Universe at the National Maritime Museum

I’ll be speaking at the National Maritime Museum, in London, this coming Sunday as part of an event called ‘Envisioning the Universe’. The day will consist of talks, debates and discussions about the science and art of astrophotography. My fellow panellists include 2012 Turner Prize winner Elizabeth Price, author Elizabeth Kessler and Guardian art writer Jonathan Jones.

For more information and to book tickets visit the National Maritime Museum website here.

Image credit: NASA, ESA and the Hubble SM4 ERO Team

The Story of a Shooting Star – filming begins!

Over the last 12 months I’ve been working, in my spare time, on a short film about meteors. Called The Story of a Shooting Star it “follows the journey of a tiny grain of space dust, tracing its origins all the way back to the birth of the Solar System before exploring its final fleeting moments blazing across the night sky as a meteor”. Having spent a while scriptwriting and researching I recently started filming for the project.

In May I spent a fascinating day at the Norman Lockyer Observatory, in Devon, with the Solar, Planetary & Meteor group there learning about radio meteor detection. And this past weekend I filmed in the stunning surroundings of Dartmoor National Park. I’ll be posting occasional updates on the film (and hopefully some short clips too) here, but for now here are some pictures from the first few days of location shooting.

The Norman Lockyer Observatory on day one of filming. Credit: Will Gater

It might not look like much, but this antenna can detect meteors. Credit: Will Gater

Ping! A meteor is detected vaporizing high up in our atmosphere. Credit: Will Gater

Twilight on Dartmoor, a truly stunning sight. Credit: Will Gater

Some serious peering going on in this shot. Credit: Will Gater