Noctilucent Clouds (NLC) are a lesser known wonder of the Night Sky. These glowing clouds captivate viewers during astronomical twilight during the summer months in Canada. (May-August in the Northern Hemisphere and November-February in the Southern Hemisphere) Typically seen between 45 and 60 degrees latitude.
They become visible once the sun is below the horizon and can be seen for a few hours after sunset or before sunrise. Due to the short window of opportunity to witness these glowing clouds, many people don’t realize they are actually seeing the rare NLC.
What causes these wonderful glowing white clouds? These clouds are in the highest limits of Earth’s atmosphere, up to 80km high, the icy crystals are reflecting the sunlight during Astronomical twilight. Normally clouds are close enough to earth to remain in the shadow once the sun goes down, NLC however, continue to reflect the sunlight. This is because they are a lot higher than normal cloud cover, making a striking contrast to typical clouds in the night sky which appear dark. NLC can only form when water particles are available to form ice crystals in the mesosphere, which is the highest parts of our atmosphere and are only visible for a few short months, during a few short hours each year.
This year the noctilucent clouds have been putting on a remarkable display in Saskatchewan, having seen them on a regular basis since late May. These clouds come into view once the sun goes down and the light is reduced on earth but still reaching into the atmosphere to reflect off the extremely high cloud cover. Finding them increase in intensity as it gets darker until around midnight (in central Saskatchewan) is when they fade to the lowest views of the northern horizon, before picking up again in the last moments of Astronomical twilight in the early hours of the morning.
Reflecting off the water, the clouds are so bright they increase the overall exposure of the scene. Although these images are captured well into Astronomical twilight, I was able to reduce the shutter and ISO dramatically due to the increased light. This allows for sharper images and less post processing to really pull out the detail.
Since the conditions have to be right, the time of year is very narrow and your geographic position on earth all considered, noctilucent clouds are a rare natural phenomenon to see. Much like the Aurora Borealis, I believe they are very hard to predict, but when you do witness the beautiful whimsical glowing cloud display, it’s a magical and memorable moment. The patterns change, the intensity shifts and the colours it pulls from the horizon make beautiful photos to remember the night by.
Two years ago I captured NLC for the very first time. I didn’t know what I was getting in my photos, it almost looked like light pollution in an area where I knew there was none. I went home and immediately began to research and learnt about this wonder I just witnessed. Never know when Night Photography leads to learning something entirely new! Like glowing clouds? I had no idea. Now, I can spot them instantly and know exactly what I am looking at.
In early June I was heading out to a nearby lake to hopefully catch some summer aurora, but the NLC stole the show that night. Shining so bright even active aurora wouldn’t be visible, I spent a few hours capturing the changing glowing clouds reflecting off the lake.
Photography Tip: Noctilucent Clouds can become visible after sunset and begin to increase in brightness as it gets darker, until the light begins to reduce toward the northern horizon. Keep shutter and ISO low in order to not blow out the highlights and pick up the detail in the cloud formations, checking the histogram often for exposure as the light slowly shifts.
I am honoured to have had one of my Noctilucent Cloud photos selected as the Winner of the Photo of the Week contest hosted by SkyNews Magazine in June 2020. Check out their article to see the image and details.
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