Noctilucent clouds are seen at higher latitudes during the summer months glowing in the sky just before dawn and just after sunset. They are mesmerising as they twist and twirl across the night sky just before dawn.
What are noctilucent clouds?
NLC are really unusual and quite special. They are seeded by the dust of meteors, billions of years old and are found at about 80km- 100km high, the highest clouds to form above the earth. The magic of them is that they are only seen in the semi-darkness of twilight when they are lit from below by the already set sun.
They sit within the mesosphere, the very outer layer of the atmosphere on earth. Tiny ice crystals less than 1/10,000mm in diameter form these clouds, frozen when the temperature is below -123°C. Unusually the temperature in the mesosphere only reaches this level during the summer months, the remainder of the year is too warm for the clouds to form.
The presence of these clouds and their location seems to be increasing and moving further south each year. Some believe this is a result of climate change but there is so much unknown about these clouds that it is just a theory.
If you want to know more this brilliant article by Martin McKenna is worth reading. My explanation is very basic in comparison to the reality!
When can you see noctilucent clouds?
NLC can be seen between May and August in the Northern Hemisphere, and from November to February in the Southern Hemisphere. They are primarily visible when the sun is just below the horizon, about 90 minutes to two hours after sunset or before sunrise
Where can you see noctilucent clouds?
NLC are visible at higher latitudes between about 45 degrees and 60 degrees north or south. They will hover just above the horizon up to about 20 degrees. As with the aurora borealis they tend to be visible in the northern sky. You really need a clear horizon to see them in their full beauty.
Photographing Noctilucent Clouds
Photographing these clouds is hard as the light from the sun is still visible and getting the balance right can take time. The light is constantly changing so you will need to keep checking what you are getting
- Having your camera mounted on a tripod or firm surface is essential.
- A shutter release cable or using the inbuilt timer will help to get a sharper image as there is less chance of movement
- Focus on a distant light or focus in daylight and then leave focussing alone. Manual focus is essential at night
- Set the LCD brightness to the darkest possible setting
- Set ISO 400, f4 and about 2 seconds and see what you get. You may need to adjust this if the light is increasing or decreasing. It will also vary with the lens and camera you are using – this is just a rough guide
- Take a range of pictures at different exposures
- You can also take images with overlap to form a panorama or zoom in to show the details of the clouds
READ MORE: HOW TO PHOTOGRAPH STARS
It’s 3am, I’ve been dozing all night. The sun has erupted and the arrival of the energy expelled two days ago is due. The conditions are perfect for the aurora borealis; a cloud free sky and a stunning landscape. But it is still only August. At 59° of latitude it is only dark for a few hours. More than on Shetland in June but still not much. Getting active aurora in the window of darkness and no moon is a lucky moment at this time of year.
Camping at Bay of Brough on Sanday, I emerge from my pod. Half asleep. I’m beginning to wonder if I am mad. This is the third night I have been awake looking for light in the sky. Dozing between the alarm. Hoping that I don’t drift off into a world of dreams. I am almost wishing that the rain clouds would arrive so I can have a night cosy and alarm free.
I look out over the bay beyond my bed and there is a magical glow. Mesmerised by the undulating clouds I stand in the cool summer morning. The orange of dawn is there. It is still a few hours before a new day erupts but proper darkness is gone. This glow is different though, not the glow of the aurora but the glow of noctilucent clouds.
I move my camera from the corner, set up hours ago to ensure it is focussed and start to take pictures as the glowing clouds move in waves and wafts across the sky. A slow movement like smoke from a winter chimney. Dancing across the sky, changing and wrapping around each other in shapes they become brighter as they change.
Standing in my pyjamas in the cool warmth of a northern summer night I feel the excitement build. The same feel that I get when the aurora borealis starts dancing, but without the winter chill that is normally present. Not knowing how long the clouds will last or what shapes and forms they will take, excitement like that of a child at christmas takes over. Hoping that they don’t vanish before my eyes but stay until the light of dawn burns them into a memory, I take as many images as I can.
Slowly as the light of a new day intensifies the clouds and stars fade, gone for another night, maybe gone for the year. Only time will tell.
As I crawl back into my warm bed, buzzing but tired I wonder if anyone else on the campsite knows what has gone on above their heads while they slept.