Solar Eclipse 20 March 2015

UPDATE: Teachers! Educators! Don’t miss out on the learning opportunity of a lifetime! This partial eclipse will be the best seen in Scotland and much of the UK since 1999, and the best until 2090. And you don’t need eclipse glasses to experience it. 

Indeed, looking at the Sun is a very minor part of the experience. The most incredible thing to happen on Friday morning will be the darkening of the day, as the Sun gets covered by the Moon and much of its light gets blocked out. This will create a dusk-like atmosphere; birds will start singing, insects will come out, flowers – if you can find any – may close up! This is such an unusual and rare event that I really hope every school pupil in the country will get the opportunity to experience it. The best time for this is straight after register (0900) until around 0945.

If you have eclipse glasses you could let some of the pupils use those but I understand that you probably don’t have many pairs and fear the younger children might not use them correctly. Don’t use them then! Just get outside, tell the kids not to look at the Sun, and explore the wonderful daytime darkness. I really hope you can turn this into the learning opportunity of a lifetime.

On the morning of Friday 20 March 2015 there will be a total eclipse of the Sun. Between 0830 and 1042 the Moon will pass across the face of the Sun, blocking out part of its light. The maximum extend of the eclipse will happen at 0934 for a few minutes.

A Total Eclipse of the Sun, visible from the Faroe Islands on 20 March 2015

Unfortunately the “path of totality”, i.e. those parts of the world that will see a total eclipse, is in the far north Atlantic and Arctic oceans. Residents of the Faroe Islands get a ring-side seat at the total eclipse.

Path of Totality, Friday 20 March 2015

That said, it will still be a dramatic event in the UK, south of the path of totality, as we will see a partial solar eclipse where the Moon blocks some but not all of the Sun’s light.

A partial eclipse from Anamosa, Iowa. Credit: Steve Wendl – See more at: http://astrobob.areavoices.com/page/112/#sthash.ElDDdLAg.dpuf

The further north you are in the country the more of the Sun will be obscured, but wherever you are in the UK it’ll look quite dramatic. Here’s a handy table showing what % of the Sun’s disk will be obscured by the Moon from where you are.

Town/City	% Eclipse on 20 March 2015
Lerwick, Shetland	96.8%
Kirkwall, Orkney	96.6%
Inverness	95.6%
Aberdeen	93.9%
Glasgow	93.7%
Edinburgh	93.1%
Belfast	93.0%
Newcastle	90.7%
Liverpool	89.4%
Manchester	89.1%
Birmingham	87.3%
Cardiff	86.7%
London	84.4%

Compare this with the August 1999 eclipse, where totality passed across the SW of England. During that eclipse the further south you were in the UK the better. Indeed the SW of England and the Channel Islands saw a total eclipse.  I was in Glasgow and saw an 82% eclipse. For me, this eclipse will be even better. In fact for anyone north of Liverpool, the 2015 eclipse is better than that in 1999!

Town/City	% Eclipse on 11 August 1999
Lerwick, Shetland	67.9%
Kirkwall, Orkney	68.7%
Inverness	76.8%
Aberdeen	77.6%
Glasgow	82.2%
Edinburgh	81.8%
Belfast	86.8%
Newcastle	84.8%
Liverpool	90.5%
Manchester	90.1%
Birmingham	93.5%
Cardiff	97.2%
London	96.6%

Wherever you are in the UK though it’s worth watching, but BE CAREFUL. Never look at the Sun directly, even when it’s eclipsed. Here are some safety guidelines for viewing eclipses.

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My Perseids Meteorwatch

On Monday night one of the year’s most spectacular meteor showers is set to peak.

You’ll get a great view of it if you’re somewhere dark with clear skies. But those of us stuck in the city can see plenty too.

I’ll be heading to the grounds of Glasgow Science Centre to view it, and you’re welcome to join me. A few things first:

If it’s cloudy or raining DON’T COME! I won’t be there.

I’ll be there from around 10pm, probably till around midnight.

If you want a great view then head somewhere dark, but if you’re in Glasgow and don’t want to head out of the city this is a decent site.

This ISN’T a formal event; I’ll be hanging out there and you’re welcome to come under your own steam. You’ll be responsible for your own safety and comfort; bring extra clothing, a torch, and a deck chair if you have one.

You can park in Glasgow Science Centre car park for £3. Public transport at that time of night is pretty sparse.

Glasgow Science Centre will NOT be open, so there’s no access to refreshments or toilets etc.

Thanks to Glasgow Science Centre for letting us use their outside space.

Scots in Space

I was delighted to hear that two groups from Glasgow were winners in last night’s UK Space Conference‘s Arthur Clarke Awards 2011.
Clyde Space, a “leading supplier of small and micro spacecraft systems”, was given the Arthur Clarke Award 2011 for Achievement in Space Commerce, while the University of Strathclyde’s Advanced Space Concepts Laboratory, which “undertakes frontier research on visionary space systems”, was given the Arthur Clarke Award 2011 for Achievement in Space Research.

Congratulations to both, and it’s exciting to me as a Scot and a resident of Glasgow that these two groups, located within 5 miles of one another, are leading the UK in space research and commerce.

Twilight vs. Light Pollution

A few weeks ago I was waiting for it to get dark so I could go out into my garden and use my telescope. I decided to wait until the end of astronomical twilight (when there is no light from the Sun left in the sky) so that the sky was “properly dark”, but of course given that I live in a city (Glasgow) the light pollution from street lights means that it never actually gets “properly dark”.

So I decided to figure out exactly how long I should wait after sunset before going out to observe, or put another way, at what point does light pollution take over from twilight as the dominant source of light in the sky?

Sunset behind Glasgow Science Centre

I carried out this little experiment on 28 April 2011, in my back garden on the Southside of Glasgow, under the following conditions:

Sunset Time: 2050 BST
Civil Twilight Ends (Sun 6 degrees below horizon): 2134 BST
Nautical Twilight Ends (Sun 12 degrees below horizon): 2232 BST
Astronomical Twilight Ends (Sun 18 degrees below horizon): 2358 BST
Longitude: 55.866 N
Latitude: 4.257 W
Sky conditions: 100% clear

[Incidentally, sitting out in my garden for four hours as it darkened was an absolute delight: I saw, as well as the emerging stars, many bats, some ducks, two foxes, and two passes of the International Space Station!]

Using a Sky Quality Meter I took readings of the sky brightness at the zenith every two minutes. The SQM-L makes measurements of the sky in magnitudes per square arcsecond, i.e. brightness per unit area in the sky. As a general rule, in city centres you would expect readings of 16-17, while in dark places you can get readings of 21-22. The higher the number the darker the sky. The darkest reading possible under a starry sky is around 22, as at that point the starlight itself becomes the limiting factor.

From experience I know that in my garden the darkest reading possible is around 18.5, so I decided to continue taking readings until I got fifteen in a row that were above 18.4, i.e. for half an hour the sky had not been significantly darkening. I got my first reading of above 18.4 at 2244 and the sky did not appreciably darken over the next 30 minutes.

At 2244 the sun was 13 degrees 07 minutes (13.117 degrees) below the horizon.

I graphed the results to see how they looked, and placed them alongside the projected results if I were under a dark sky free of light pollution i.e. so that the results could get as low as 22.0 at the end of astronomical twilight at 2358 BST

SQM-L Readings vs Time

Result: After sunset, and throughout civil twilight (Sun between 0 and 6 degrees below the horizon) and nautical twilight (Sun between 6 and 12 degrees) the dominant source of light in the sky is sunlight.

However shortly after the end of nautical twilight light pollution became the dominant source of light in the sky, when the Sun was a little more than 13 degrees below the horizon.

This means that, while observing from my garden in Glasgow, I shouldn’t wait much later than the end of nautical twilight to go out observing, since beyond that point the sky will not significantly darken.

CAVEAT: It should be noted that this information is really only relevant for my specific circumstances, i.e. the light pollution in your sky may be better of worse than mine, and mean that the point at which it begins to dominate twilight is different for you.

Close Encounters?

This post is about an actual event that happened to me on the night of Tuesday 4th Feb 2003, as I left work (Glasgow Science Centre). The following is entirely true, and changed my worldview in a big way. I hope you read the whole thing, and don’t dismiss any of it until you’ve read it all.

I worked late last night, leaving about 8pm. It was cold and crisp outside, and the sky was crystal clear. As I walked along the riverside to Bell’s Bridge I was busy looking up at the stars (Orion was up, and both Jupiter and Saturn we clearly visible). I passed a man with a dog and was temporarily distracted. When I looked back up I caught something moving in the sky, near Orion. I’ll explain my observations and thoughts in the order that they happened.

In the first split second that I saw something moving I realised that it was moving at the same speed a satellite would move; that was my first thought, that it was an artificial satellite. That was an initial reaction based on a split second observation, and was due entirely to the speed at which it was moving.

After I focussed on it, I saw that it was orange/red in colour, and realised that it wasn’t a satellite, as they only ever appear white as they reflect sunlight back to us on Earth. The next thing I noticed, just moments later, was that it had size; it wasn’t a point object. My reaction to that was that it was a trail from a shooting star, a puff of colour as a bit of space rock was vaporised in the upper atmosphere.

I continued to watch though, and it kept moving, at too slow a rate to be a shooting star – it was still moving at satellite-speed. In addition, there was no trail, ruling out shooting stars altogether.

All these observations and thoughts happened within the first second. As I stood craning my neck to watch it, it passed overhead, and I realised that I could make out a shape. It was almost too small to see, but I saw something like this:

It was still travelling at the same speed, roughly east to west, and I turned to watch it pass over the Science Centre. As I watched it I realised that it wasn’t quite travelling in a straight line, it was zigzagging erratically, very fast, back and forth, as it kept moving westward.

Eventually it faded from view, and I was left staring after it, my mouth hanging open. It was totally inexplicable. As an astronomer I’ve spent a lot of time watching the sky and I had never seen anything like this. I was at a total loss to explain it. At that instant I’d seen a UFO. It was totally Unidentified.

However, this lasted for only five seconds. As I stood watching the sky, dumbfounded, I saw another one, following the same path. It was the same colour, the same shape, was moving at the same speed, and zigzagging like before. But this one was bigger. It was bigger because it was lower; low enough in fact that I could see it clearly. It was a bird.

I laughed out loud (attracting a funny look from a passer-by) at how easily fooled I was. Here was me, someone who is used to looking at the night sky, and I saw something I couldn’t explain. I’m about as sceptical as they come, but in those few seconds I was in the same group as the multitude of UFOlogists who claim to have seen just such wing-shaped craft zigging and zagging through the sky in fantastic ways.

But it was just a bird! If I hadn’t seen the second bird, who knows what I’d be writing now. As it is I feel totally privileged. It was as if the Universe looked at me and said; “I’m going to show you something amazing, something that thousands of other people have seen, but that is totally inexplicable… and then, just for you, I’m going to explain.”

Ultimately it has given me a better understanding of people who claim to have seen UFOs. They might quite innocently report just such an observation and be told rudely: “It was just the planet Venus.”

“No,” they’d reply. “I know where Venus is; it wasn’t that.”

“Well, in that case, it was just a bird reflecting light from streetlights below.”

To which the upset reply would be something like: “I think I’d recognise a bird when I see one.”

I didn’t.

Shooting Stars – Part 1

Just finished filming the first of two evenings for BBC’s Countryfile programme. This evening was just some footage of me taking Sky Quality Metre readings in a brightly lit urban environment; in fact just outside the BBC Scotland building and Glasgow Science Centre.

It was, amazingly, a clear night, but even with no clouds we could only make out a few dozen stars through the glare of the local lights and the glow of the light pollution from the whole of Glasgow. If you’re interested, the SQM read 17 or so.

I set my DSLR camera up to take some pics of the filming, just for posterity, and in between I took  some scenic shots of the viscinity, like this nice one of GSC and Glasgow Tower, showing the skyglow.

The best part of the night though, by far, was seeing the ISS flare up towards the WSW and having just enough time to set my camera up to capture this shot of it passing through Orion! Didn’t have enought time to figure out exposure times to get the best possible shot, but still, my first attempt at astrophotography paid off big time!

Off home now, chuffed with my pic, and looking forward to tomorrow night’s filming in Glasgow Planetarium and then later in Galloway Dark Sky Park.