|Lunar Fogbow, Northern Ireland Images by Martin McKenna (nightskyhunter.com).
"I captured my very first lunar fog bow on camera during the early morning hours of October 9th 2014. I had left home that morning at 03.00 to hunt for distant lightning over the Irish Sea. I drove to the top of Glenshane Pass so I would have a high vantage point. With the exception of a few distant flashes I didn't get rewarded.
The night was beautiful though with a brilliant waning full moon, stars and fog for company, then just as I was thinking of calling it a night I saw a strange apparition at the bottom of the field in which I stood, it looked like a glowing heavenly form which was brighter than everything else in the area, then I realized what it was - a rare lunar fog bow in the process of manifesting in front of me.
Between 04.00 and 05.00 I was treated to this most beautiful display with the ghostly white bow in the field with the stars and planet Jupiter to the upper right. With the naked eye I could see an orange crown to the upper section of the bow,
I took these images with a 10mm lens using my Canon 600D at ISO800 between 20 and 28 sec's. I just had to jump into the grass to get a shot of me with the this prize catch despite getting soaked with dew in the grass - which in places was up to chest height. I have photographed many moonbows over the years and have only ever observed three true lunar fog bows and on each occasion I never had a camera - until now. I had such a great experience high on the mountain in the middle of nowhere watching this wonderful phenomena and I was delighted to have finally ticked it off my list, I'm now hooked and will be on the hunt for more."
All images ©Martin McKenna, shown with permission
|Fog, or mist, and bright moonlight shining clearly through it are essential. Plus a reasonably dark sky. That reduces the opportunities to see a lunar fogbow considerably. Their cousins, lunar rainbows, are similarly elusive.
Incoming light waves enter a droplet and are refracted. Some are reflected by the opposite side of the drop. They refract once again as they leave. The multiple waves overlap, interact and spread - diffract - while all this happens. The outcome is a broad and diffuse bow almost devoid of colour.