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:
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.
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