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   Observing - Getting started  

Halos are visible much more often than rainbows, usually at least once or twice a week. To find them successfully, shield the eyes from excessive glare and know their sizes in the sky.
  
Shield the sun

Halos are much more easily seen when the sun is shielded. Use a building, a tree, a post or a hand. Always shield both eyes and never look directly at the sun.

Colourful 22° halo and fragment of upper tangent
arc. Sun 20° high 27th April 01. İBob Fosbury

   
Halo sizes

The most common is the 22° radius circular halo. It is easily found in the sky. Stretch out your arm and spread your fingers wide. The distance from the thumb to the tip of the little finger is then about 20°. Cover the sun with the thumb and the 22° halo will be near the tip of the small finger.

22° circular halo and circumscribed halo. 21st May 01
Sun elevation 57°. Photo Les Cowley