Observation Tid-Bit #4

Observation Tid-Bit #4 - “Angular Distance in the Distance.”

- by Aaron Clevenson

You’re out in the dark. Maybe you are documenting Meteors or Satellite paths. You need to be able to estimate an angular distance. But how? The protractor is not available, and your surveying equipment wouldn’t fit in the car. What can you do? Well like everything else in the world, when technology is just not there, do it manually – with your hands.

If you hold your hand at arms length from your face, different parts of your hand can be used to estimate angular distances. Here is a table to help you make those “in-the-dark” measurements:

- Your pinky is about 1 degree across (that’s two full moon widths).

- The other three fingers (minus the pink) are about 5 degrees.

- Your fist, across the knuckles is about 10 degrees.

- The distance between your outstretched pinky and outstretched pointer finger is about 15 degrees.

- The distance between your outstretched pinky and your outstretched thumb is about 20 degrees.

You have small hands? Not to worry, your arms are probably a little shorter too. This means that although your fingers may be smaller, they will appear larger to you because they are closer to your eyes. It all averages out.