The people of Yogyakarta on Tuesday afternoon (4/1/2011) were surprised by the rainbow ring surrounding the sun. The phenomenon which is usually called as solar halo was seen clearly in the Yogyakarta sky around 10.15 to 11.15 hours.
The rare phenomenon attracted people. Many people spent time to witness it. Some captured the natural phenomenon with their cellular phones or digital cameras.
Many people were amazed watching the natural phenomenon. However, not a few of them were worried and even panicking and considered it a bad sign. For common people, the phenomenon is disturbing because they do not know that it is an ordinary natural phenomenon.
Some members of UGM academic community were also surprised by the solar halo. Budi, a member of staff was busy capturing the halo with his SLR camera, he even went to the yard to get the best results.
Budi admitted he had seen the solar halo for several times, but only this time he was able to capture it. “This is the fourth for me but I managed to capture it now because the previous halos were not clearly visible and only occurred a few minutes,” he said.
Meanwhile, several other people said that they got headache after seeing the glare of the sun. “It is too glaring to see the halo without sunglasses. I feel dizzy,” said Dewi, student of Faculty of Veterinary Medicine.
An Ordinary Phenomenon
Prof. Dr. Sudibyakto, M.S., UGM climatologist, said such phenomenon normally happens. This phenomenon has no relation with natural disasters, such as earthquakes. The halo surrounding the sun is the sunlight deflected by vapor particles in the atmosphere. The water particles have the ability to deflect or refract sunlight. In the afternoon when the sun is aligned perpendicular to the earth, the biased light is less. “That’s why people see a dark circle surrounding the sun,” he said.
Sudibyakto added that solar halo is similar to the rainbow in the morning or night after rain. Rainbow curve is often seen under firmament because vapor particles that deflect the sun light is in the low angle. “In inclined position, water particles’ ability to retract light is bigger so colors appear more clearly,” he added.
In the afternoon, as the sun is perpendicular to the earth, the ability to deflect light is less so the colors get limited. The colors are also darker because the vision to the sun is blocked by dust whereas in the morning when the air is clean, the color that appears is reddish.