A Green Flash from the Sun . ... It's a green flash from the Sun . ... The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A green flash is also visible for a rising Sun , but takes better timing to spot. A dramatic green flash , as well as an even more rare blue flash , was caught in the above photograph recently observed during a sunset visible from Teide Observatory at Tenerife , Cannary Islands , Spain . ...