Please explain 22 degree halo

[Gail Holt]

Good Morning,

Thursday’s cloud-a-day was a beautiful and spectacular 22 degree halo, and the explanation is that it is so named because the angle between the direction of the Sun and that of any point on the halo is always 22 degrees. I simply can’t visualise where this angle lies… can someone do a geometric diagram showing me just where this angle is? Or maybe my confusion is to do with the line of the direction of the sun? A diagram would help.

Many thanks.

Gail

[Michael Lerch]

..Its not an angle..its a distance..Degrees in this case refers to astronomic or celestial degrees..the sky is measured in degrees of a celestial dome..360 degrees in a circle..Hope this helps..Hold your hand out..Fully extend your arm. Spread your fingers apart. The distance between your tip of the thumb and the tip of your pinky finger is 20-22 degrees. So if you put your thumb on the sun the 22degree halo is out there where your pinky finger tip is..Have Fun!

[Gail Holt]

Ahhhh… thank you so much.  I was thinking of geometric angle degrees not celestial astronomic degrees. It now all makes sense… I should have twigged being a (very) amateur astronomer.

[Hans Stocker]

Gail, here you can find a nice diagram that shows why it is called a 22 degrees halo: diagram

[Ruth Quist]

Hans and Michael, thanks to both of you in explaining the interesting 22 degrees.  Like Gail, it is a hard concept to understand.

[Gail Holt]

Thanks all, especially Hans for the diagram.

[Author]

Posts