A captivating solar halo, appearing as a luminous ring around the sun, has recently been observed in the skies of Lạng Sơn and Thái Nguyên provinces in northern Vietnam, sparking interest and social media shares among residents.
According to the Hanoi Association of Astronomy (HAS), referencing Earth Sky, this phenomenon is identified as a 22-degree halo. These halos are created by the refraction and reflection of sunlight through millions of hexagonal ice crystals suspended in high-altitude cirrus clouds. The angle of minimum deviation for red light is less, making the inner edge appear reddish, while the outer edge appears bluish.
Experts caution that looking directly at the sun, even with a halo, can cause serious eye damage. It is crucial to use indirect viewing methods or specialized eye protection, such as eclipse glasses meeting the ISO 12312-2 international standard, to prevent harm.
The appearance of a 22° halo can also be an indicator of approaching storms, as cirrus clouds often precede weather disturbances. However, these clouds can also occur without any associated weather change, making the halo an unreliable sole predictor of bad weather.
The 22° halo is one of the most common types of halo, appearing as a ring around the Sun or Moon with a radius of about 22°.
Safety while viewing a Solar Eclipse
Never look at the sun through an unfiltered camera lens or telescope.
Always supervise children using solar viewers.
If you don't have eclipse glasses or a handheld solar viewer, you can use an indirect viewing method.
How to View the Solar Eclipse
Indirect viewing is the safest, create a homemade pinhole projector.
Direct viewing requires special glasses.
How to Safely Photograph the Eclipse
Turn off the flash.
Lock the focus on distance, or “infinity.”
The solar corona, which looks like a halo, may be visible during the totality, and it is safe to remove your solar glasses at this time.
This article is based on our author's analysis of materials taken from the following resources: Wikipedia, Bureau of Meteorology, NASA Science.