Red sky at day, hurricane on the way

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Red sky at day, hurricane on the way

Ophelia sun close up.jpg

Long before we had satellites and super-computers to process weather data, we had to trust our senses. And we came up with a series of weather sayings to aid us. The most famous of these is undoubtedly ‘Red sky at night, shepherd’s delight; red sky in the morning, shepherd’s warning’.

But I don’t think I ever came across one to describe what I saw this morning. With ex-hurricane Ophelia barrelling towards the island of Ireland, everyone here is on high alert. The schools are closed. The universities are closing. The island is hunkering down in anticipation of what’s coming. But, this morning when I woke, the sky had a strange orange hue. There was plenty of cloud, but everywhere had a colour cast, the kind of colour you can get when a particularly strong sunset is happening above the clouds, strong enough to shine through.

But, weirdly, as the morning progressed, this hue didn’t disappear. Long after the golden rays of sunrise should have dissipated, still it endured.

Then the sun broke through a gap in the cloud. And at 10.00 am, a good two hours after sunrise, there was the orb hanging in our sky, glowing a burnt orange colour.

There are only two things that can make the sun red - first, when it’s low in the sky at sunrise and sunset, and the light passes through more of our atmosphere, scattering all but the red wavelengths.

Rayleigh scattering.jpg

And secondly, when there is a lot of dust in the atmosphere, also scattering the light.

It was too late in the morning for the former, so it could only have been the latter. And a quick bit of research revealed that was indeed the case. This record-breaking and very unusual hurricane had swept up dust from the air above the Sahara desert when it was off the coast of Africa near the Azores, and had swept this dust north with it.

Source: EUMETSAT

Source: EUMETSAT

SOURCE: @wx_radar The dust concentrations in our atmosphere. You can clearly see the plume of dust that has been dragged up by the hurricane.

SOURCE: @wx_radar The dust concentrations in our atmosphere. You can clearly see the plume of dust that has been dragged up by the hurricane.

As the sunlight passes through the dust, the longer wavelengths are scattered by the the particles. This scatters the blues and greens, letting the oranges and reds through. This happens at sunset as the low angle of the sun means the light travels through a greater distance of the atmosphere, and more and more of the blues and greens are scattered, leaving only the oranges and reds. But this morning’s dust meant that this effect could be seen, even after the sun had risen much higher in the sky than normal. Cool science - and a totally eerie and creepy effect, with the former hurricane headed our way!

So, red sky in the morning, shepherd’s warning. How about red sky during the day, hurricane’s on the way…?!?


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New series of mini eBooks launching

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New series of mini eBooks launching

eBook cover not so dark after all.jpg

Brand new mini eBook series launches today, with my latest title, "Not so dark after all". And better still - it's entirely free!

Anyone who hangs around my social media pages for any lenght of time will know that, on occasion, I like to put pen to paper (or, more properly, finger to keyboard) in an attempt to string together a few words about my experiences on my photographic journey.

As a result, I've ended up with dozens and dozens of blogs, covering a wide range of photographic topics and themes. They are, of course, available as a back catalogue on my website.

But I've decided to experiment with a new initiative - making a selection of them available offlien too in eBook format. And I'm offering these mini eBooks entirely free!

I'm staring with my last blog on my experiences photographing the airglow at the Giant's Causeway the other week. The eBook includes the images and stories in the blog, but with some added content not available elsewhere.

To get your free copy, all you have to do is click here to download your eBook. I'll not be asking for any email signups or anything else like this. This is simply my gift to anyone who might be interested!

I'd love to hear from you if you think this is a good idea, and if you'd like more content presented this way. There's a bit of work in it - but I enjoy it and am happy to do it if folks think it might be interesting or of help.

Feel free to comment on my social media pages (or even here, if you like) to let me know.

In the meantime, enjoy this eBook!

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Not so dark after all

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Not so dark after all

Airglow, gravity waves, and why the deepest darkest night is not quite as deeply dark as first it may seem...


There’s a reason why my eBook and camera club talks on astrophotography are called ‘Don’t be afraid of the dark.’ It’s intended as partly metaphorical; for some, using their camera in low light settings can be well out of their comfort zone and something that fills them with a degree of trepidation.

But it’s also partly intended in its literal sense. To photograph stars, you have to go to some very dark places. Places where you can barely see or make out what’s around you. And places where the darkness sends the mind and imagination off in all sorts of scary directions at times. But the truth remains: the darker the better, when it comes to stars.

The thing it, though, I have come to realise that that is only part of the truth. Yes, you need to be in dark locations. But sometimes this very darkness is the very thing you need to enable you to see the light (and I mean that literally, not metaphorically!)

For it turns out that the night sky is never really quite fully dark. On clear nights, of course, there is the star light itself, twinkling down gently on us. And I have been out on occasions where the starlight alone was so clear and so bright that I was able to pick my way over the uneven columns of the Giant’s Causeway without the need for a torch.

But there is something other than that, shining at night, meaning that the very dark skies themselves shimmer with light, albeit very faintly. And I had my most recent experience with this just a couple of weeks back during my last astrophotography workshop.

Workshop wonders

The workshop folks, enjoying sunset before the serious astro business began.

The workshop folks, enjoying sunset before the serious astro business began.

After capturing sunset along the sublime Causeway cliffs, we had just finished photographing the Milky Way to the south west, rising up like a majestic celestial swathe of soft light above the cliffs behind the Causeway.

I said to the guys that I would point my camera north and see if the aurora that was possible that evening was in fact there. And indeed it was, albeit a faint one. But, when I took my couple of test shots, something odd seemed to be happening. It appeared like my white balance was all thrown off. There was a strange green hue across my whole shot, something bigger and more extensive than the aurora itself.

At first, I thought it was a fault with the camera, and I tweaked my settings to try to see if I could resolve it. But, try as I might, the ‘fault’ remained. And it was only then that the realisation dawned on me - this was a phenomenon called airglow, the feature that is responsible for the night sky never being fully dark.

I had first photographed airglow earlier this year, on one particularly cold night at the Causeway (where else?!).

Airglow over the Causeway from January 2017 - and there's the Milky Way to the north, with the pinks of the North America nebula shining through right at its heart.

Airglow over the Causeway from January 2017 - and there's the Milky Way to the north, with the pinks of the North America nebula shining through right at its heart.

Airglow earlier that same January evening, this time behind the unmistakable outline of Dunluce Castle.

But this was airglow like I had never seen it before. It was extending far up into the night sky and was so intense that it cast such a strong green hue across my whole shot. So strong, in fact, that the entire ocean itself was glowing green on my photos, reflecting back some of the light that was cascading down from above. Indeed, even the puddles of water in the hollows of some of the columns from the day’s earlier rain glowed green. This was truly a beautiful sight, and it was amazing to witness it during the workshop.

The green hues of structure filled airglow reaches high into the sky, whilst the subtle aurora along the horizon throws up some faint pillars, as if to say, "Don't foget about me!"

What is airglow?

Airglow happens when the molecules high up in our atmosphere (more than 80km high) emit photons of light. During the day, these molecules are ‘excited’ by energy from sunlight and, in their excited state, the atmospheric molecules such as O₂ break apart into oxygen atoms. They store the energy they picked up for a few hours, then the atoms recombine into molecules once again and the excess energy is given off as light (in the case of oxygen, this light is green).

Airglow happens during the day, but the sunlight from the sun makes it impossible for us to see it. And it carries on into the night; however, on the vast majority of nights, you’ll not really notice airglow, even in long exposure photos - in large part due to the fact that night airglow is only about one thousandth the level of the daytime emission.

However, every once in awhile, the emissions of light from night time airglow become more pronounced. And, if you happen to be out photographing under conditions like that, your long exposures on your camera will pick up a strange glowing wash of (most commonly) green across the sky. It turns out that, in the past, there have been times when airglow was very visible even to the naked eye, and so bright that people have been able to see far off mountains or even read a newspaper. In fact, Pliny the Elder reported that “the phenomenon commonly called 'nocturnal sun', i.e. a light emanating from the sky during the night, has been seen during the consulate of C. Caecilius and Cn. Papirius, and many other times, giving an appearance of day during the night.” More recently, such bright airglow nights have not really been reported so much. But what might explain the variation in airglow? Why is it brighter some nights than others?

Gravity waves - ripples in the sky

A recent study for the Geophysical Research Letters in the USA has suggested a mechanism that might explain these variations. Scientists have found a link between large waves in the upper atmosphere, produced by weather events lower down. When the peaks of some of these waves converge, they can produce more intense localised airglow that might persist for a few nights in a particular location (they estimate that more intense airglow can occur on about 7% of nights at some localised places somewhere on Earth).

Not only was the light from the airglow bright enough to light the sky and the ocean, but it rippled with structure, courtesy of some gravity waves sweeping up from below.

And here we were, standing on the ancient stones of the Causeway, staring up at this wonderful sight rippling through the sky above us. But that was not all that was going on. For on closer inspection, it looked like there were thin wispy clouds trailing across the sky. At least the photos suggested that. In reality, the skies were crystal clear and there wasn’t a sign of a cloud to the naked eye. So what was the camera picking up?

It appears that sometimes the airglow is not always a homogenous glow of light, but that it can sometimes have structure and features in it. What looked like clouds, were actually waves in the very light that was shining in the darkness. And, my goodness, were they beautiful. Ripples in the sky, shining down on the ripples of the ocean below.

It appears that these ripple structures are also produced by waves, known as gravity waves. The most common example of gravity waves are the waves formed on the sea by the wind. They form when the fluid is disturbed from a position of equilibrium. The wave initially moves in one direction, and gravity acts to pull it back towards its starting position - but it ‘overshoots’ and begins the wave-like undulations we see on the ocean.

Such gravity waves can also form in the atmosphere. For example, when air is displaced upwards over a mountain, the column of air above the mountain is displaced upwards, knocking the air out of its equilibrium state and producing the oscillating gravity waves. As these waves move up into the upper atmosphere, up to where the airglow is occurring, it can cause oscillations there which produce wave-like structures in the airglow.

And that’s exactly what we were seeing. Dimples, undulations, ripples - all sort of glorious structure in the night sky above us. Gloriously beautiful to behold.

Noctilucent structure

Gravity waves are responsible for other wonderful atmospheric patterns. The delightful noctilucent clouds - those ephemeral night glowing clouds of mid summer - are famous for their beautiful striations and herringbone patterns. The patterns too are the result of the undulations of gravity waves, propagating upwards from the lower atmosphere.

Gravity waves causing the distinctive ripples of the noctilucent clouds above Carrick Castle.

A subtle noctilucent cloud show at the Causeway, still with those tell tale gravity wave patterns.

A time lapse of a noctilucent display in 2015 - followed by the most stunning of mid-summer aurora shows, thrown in at no extra cost!

Kelvin–Helmholtz

But you don’t need to go to the highest reaches of the atmosphere to see them in action. Lower down, in the troposphere, when you get a band of cloud with another band of air above it moving at different speeds, the upper band can disturb the lower band, settling up the wave undulations known as Kelvin-Helmholtz clouds, themselves a beautiful sight to behold.

 


So, next time you’re out shooting the stars above us, if you seem to find that your white balance is off, don’t immediately assume that there’s a fault with your camera. Look carefully once more, and you too may be witnessing yet another one of our atmosphere’s night light displays. Sure, there’s hardly even enough dark to be afraid of in nights like that!

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All for the sake of 15 minutes...

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All for the sake of 15 minutes...

I like to think I’m generally a pretty upbeat guy. I tend to think of the proverbial glass as being at least half full (often with the chance of a refill not too far away). I have a strong tendency to get excited about things I’m enjoying. I know the old pessimists charter says, ‘Don’t get your hopes up and you’ll never be disappointed,’ but I tend to be happy to run that risk and embrace life with enthusiasm.

But then last Thursday happened.

I was out aurora chasing with my good buddy Johnny Baird. The stats were impressive, we were totally game on for the first decent viewing of the new season. Johnny and I were out hunting, and we were standing near Big Collin mountain looking down on Slemish Mountain - under a bank of cloud that resolutely refused to show any signs of shifting. We were seeing photos of the lights coming in from across the UK. But we were seeing nothing. Eventually, at 1.15 am, I decided to call it a night. Johnny, who didn’t have to get up for work the next morning, decided to head to Slemish for once last go.

Fifteen minutes later and I’m in bed, whilst Johnny is being treated to a great display, as the cloud cleared at just the right moment.

And I was gutted. Truly gutted. For the sake of 15 minutes, I had missed it all.


Fast forward to Sunday night, and I found myself out on the North Coast. The forecast was for showers - often the kind of weather that gives dramatic light and some great photo ops - and I headed for Magheracross carpark near Portrush. To sit in my car, with the wind and rain buffeting me for the next hour. Like Thursday night, I was clouded out. Like Thursday night, there were no signs of things clearing. But unlike Thursday night, I wasn’t going to miss out on any fleeting chance I might have. So I sat on. In the car. In the rain. And waited.

 Looks like I wasn't the only one determined to brave the inclement weather...!!

But nothing was happening. Nor did it seem likely too. I should just head on, I thought to myself. I need to call it a night. But memories of Thursday night echoed around in the back of my mind. Okay, I thought to myself, just 15 more minutes. Maybe I’ll get lucky

And then, just like for Johnny on Thursday night, the clouds cleared, the rain died off a bit. And I had my opportunity. Quickly, I hurried into position. The light indeed was dramatic. But the rain picked up again almost immediately. Too wet for my camera. ‘Come on, rain,’ I shouted, ‘clear off!!’

The dramatic light that greeted me as the heavy rain passed - but there was still a lot of rain at this stage, and I struggled to photograph anything without drops of water on my lens and filters!

And, as if by command, it did. At least it died back off enough for me to have a go at a shot. Yes, it was still windy. Yes, there were spots of drizzle. But more than that, a massive rainbow shimmied into life behind me, around Dunluce Castle and the Wishing Arch.

As the sun was so low in the sky, and because I had an elevated viewpoint at the cliff top, the arc of the rainbow not only arced through the sky overhead, but it started to swing in below me over the ocean below, accompanied by a faint but discernible secondary bow around it.

The light had a lovely quality about it, managing somehow to be both soft and clear at the same time. The sidelight off the chalk cliffs pulled out details there. But the light in the distance, helped by the reatreading rain, covered the background with a delicate softness.

I set up my camera as quickly as I can, hoping it would hold steady in the wind and on the tufts of grass, and snapped away, trying not to bounce around too much in my excitement. Within a few minutes, the bow had faded as the rain moved East. But I had caught it. I had given it just 15 minutes more - and it had paid off.

I’m still gutted about missing the aurora. I may not have caught pillars of green thrusting up into the sky last Thursday. But to have caught the many colours of the rainbow, arcing gently above and below me, that kind of felt that it made up for it, at least in part. My glass was certainly more than half full on Sunday, don’t you think…?

After the sun had set, there was still nice, dramatic light towards the horizon, so I turned my attention back this direction for a bit.

Finally, before the light began to fade, I came back over for another longer exposure shot of the water and waves breaking against the headlands.

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When one Typhoon isn't awesome enough...

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When one Typhoon isn't awesome enough...

I may well be known most for photographing the skies at night, when they're full of stars and (hopefully!) aurora shows, still I can't resist my annual visit to the Airwaves air show in Portrush. I don't have the camera gear that allows me to get up close to the planes with a zoom that weighs the same as a baby elephant, but there is something about the atmosphere, the skills and (when the Typhoon or Lancasters arrive) the noise that fills the skies over Portmagic. So I offer below a selection of shots from 2017, a tribute to the incredible skills of the brave men and women who through themselves around the skies mercilessly for our thrill and excitement!

How many Typhoons?!

The main shot I took this year was of the Typhoon. My 200mm zoom isn't really long enough to pick out the details of the bolts and rivets on the plane, so I decided to go for something a bit different - a composite shot of the plane banking around, its afterburners glowing a vivid orange against the pale blue of the sky.

To capture this, I put my camera on high speed burst mode to catch the plane as it banked. Back at the computer, I loaded in all 17 separate shots into one Photoshop file and then began the painstaking job of manually aligning them into this arc. I used layer masks to paint in each of the photos of the Typhoon, resizing them a bit to increase the sense of perspective. Then I needed to nudge each of the planes subtly so that the arc was smooth. Finally, the background sky need quite a bit of work to smooth out the blotches (I did this through a combination of using Frequency Separation and Gausian Blur to remove the main parts, and by putting an overlay of a clear shot of the sky to smooth out the sky even more). It took me a few days to complete this, but I enjoyed doing it and am quite pleased with the outcome.

Typhoon behind the scenes.jpg

I must admit that I'm a fan of shots that show the planes in context. This is, after all, the Portrush airshow, and if I can capture something of the landscape in the shots too, I'm happy. So here's the Typhoon with the unmistakable outline of Lacada Point at the Causeway in the background.

The Catalina

I managed to capture this amazing plane in context too, this time with Dunluce Castle along the cliff top behind it.

The Red Arrows

Of course, no collection of air show shots would be complete without the iconic sights of the Red Arrows in tight formation, showing off the most incredible of piloting skills.

And I couldn't resist a wee composite here too! This time, I used the program Starstax (which I normally use for star trails shots) to stack some photos of the burst out of the Red Arrows. As the planes are always so small in a wide angle lens, it's hard to do this kind of shot justice. But I quite liked the bit of fun this was putting it together.


Thanks to my good buddy Chris Ibottson - fellow landscape photographer and Typhoon admirer - for the idea for the title for this blog!

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