Check out this "green flash" as seen from St. Pete Beach, Florida on March 14th, 2021.
DOES THE GREEN FLASH EXIST?
Yes! The Green Flash sounds like a super hero, but it is a real-life optical phenomenon. Though, just like the Green Lantern and Green Hornet, it can be just as elusive... unless you know the type of conditions necessary to create a green flash. (Hint: keep reading)
WHAT IS A GREEN FLASH?
The green flash is an optical phenomenon that occurs on the upper rim of the Sun during sunrise or sunset. Specifically, it is the result of a mirage and dispersion of sunlight.
WHEN DOES THE GREEN FLASH OCCUR?
There are several atmospheric and geographical conditions that must be met to observe a green flash. (Note: you are most likely to see the green flash when you have an unobstructed view of the horizon, such as at the beach overlooking hundreds of miles of open sky)
Clear Skies: You must have a clear view of the Sun as it is dipping below the horizon. Even thin cirrus clouds on the horizon can obstruct the view of the flash.
Calm Winds: Green flashes can occur on a breezy day, but the most pronounced flash will be visible when the winds are calm.
Temperature Inversion or Differential Between The Air Immediately Above The Water/Ground and The Air A Few Meters Above the Water/Ground. Example: mild ocean water and cool air temperatures (or vice versa) can create a drastic temperature differential necessary for the flash to occur.
HOW TO TELL IF CONDITIONS ARE IDEAL FOR A GREEN FLASH?
Notice how the distant buildings in this photo appear distorted. This means that the air temperature varies greatly between the surface and the air slightly higher. If you see a view like this during the day or evening then you may want to stick around for the sunset. Note: you can use distant trees, buildings, or ships to identify the presence a mirage.
You can also look at the setting Sun and see if you are going to be treated to a green flash. Check out this photo taken a few minutes before the green flash shown at the beginning of this blog. Notice how the bottom rim of the Sun is not completely circular, almost ragged. The appearance of a ragged or even hour-glass shape to the Sun as it is setting (or rising) indicates the presence of a temperature inversion or differential.
BEST WAY TO VIEW A GREEN FLASH
You will only be able to view the most pronounced flashes with your naked eye. Technically, a set of binoculars or even a telescope would provide the magnification ideal for green flash viewing. But, you don't want to stare directly into bright Sun!
The best and safest method is to view the setting Sun through the LCD viewfinder on a camera. A cell phone camera is adequate enough to capture the green flash. But, the greater the zoom capability of your camera, the better your view will be of the flash. The photo of the green flash on this blog was taken with a Canon 70D DSLR with a 300mm lens.