Distance Off by Winking

You can make a fair estimate of your distance off using the Wink Method (see Figure 12.6). This needs no instruments and little arithmetic and there is no maths using the appearance of features in judging distance off which can be surprisingly accurate (check what to look for in Figure 12.7).

Known distance 300 m

Hold your arm out. Place the edge of your finger at one end of your known distance. Close one eye.

Eye Thumb Distance

Open your closed eye. .^J Your finger appears to 'jump'

sideways and in this case jumps to almost the middle of your known distance. ^DjVlPVour - knoWndistanceL^fc ur finger has jumped across it, in this case it is just under half, say 130m. ^Multiply the answer by 10 ^■^SHdyou have ■ your distance off.

12.6 The Wink Method or Distance Off

SERIAL

DETAIL

DISTANCE

1

Clothing can be seen and people's faces begin to be made out.

One cable (0.1 nm)

2

The colours on people's clothing can be made out.

0.25 nm

3

A person looks like a wooden post.

0.5 nm

4

Largish trees can be made out individually.

1.0 nm

5

Windows and chimneys can be made out on buildings.

2.0 nm

6

Large houses can be made out.

5.0 nm

7

Church towers and steeples become visible.

8.0 nm

12.7 Judging Distance

12.7 Judging Distance

0 0

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