Caption: How to measure angles approximately using your hand---in the form of spread hand, fist, and finger.

Now everyone's combination of hand and arm is a bit different---we are all unique---but just approximately at arm's length:

1 finger ≅ 1° 

1 fist ≅ 7--10°

  (depends on whether you 
   count the protruding 
   thumb or not)

1 spread hand ≅ 18--20° 

  (all from yours truly's own 
   measurements).  

You CANNOT expect high accuracy/precision.

Examples of astronomical angles are:

1. The separation between stars.
2. The altitude (an angular height in astro jargon) of an astronomical object above the horizon. Altitude is measured along a great circle that passes through zenith.
3. The angular diameter of the Moon.

Note: An angular diameter is the angle subtended by the diameter of a spherical astro-body (or any spherical body) as measured from some observation point which is usually the Earth for astronomy.

Credit/Permission: © David Jeffery, 2003 / Own work.
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