alien_angular, angle measurements with the hand

    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).  
    The above results are convenient for judging angles on the sky.

    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.
    Image link: Itself.
    Local file: local link: alien_angular.html.
    File: Alien images file: alien_angular.html.