Finding North Using a Watch (Northern Hemisphere)

Intro: Finding North Using a Watch (Northern Hemisphere)

The sun rises in the east and sets in the west. At midday the sun will be due south. If you observe the suns movements you can get an idea of the cardinal points.
But what if you don't have all day and you want to find North/South now?

You will need:
1. A wrist watch.
2. The Sun.

STEP 1: Aline Your Watch

Move your watch around until the hour hand is pointing at the sun (As its difficult to take photos facing the sun, I put a nail in a piece of wood and use the shadow to indicate the position of the sun).

STEP 2: Imagine Lines

Imagine a line traveling through the 12 O'clock (green line) and another line pointing towards the sun (red line). Divide the angle that is made in half and this point will indicate Due South (yellow line).

Before noon you measure the angle created between the hour hand to the 12 O’clock, in a clockwise direction. After noon you measure the angle between the hour hand and 12 O’clock in an anticlockwise direction.


We will use the example of 7 O’clock:

At 7 am, we make an angle from the hour hand to 12 in a clockwise direction (7,8,9,10,11,12). This gives us a 150 degree angle, so South is at 75 degrees, half way between 9 and 10.

At 7 pm, we make an angle from the hour hand to 12 in a anticlockwise direction (7,6,5,4,3,2,1,12). This gives us a 210 degree angle, so South is at 105 degrees, half way between 3 and 4.

I hope this clears it up for you, but the best way to understand this is to go outside and try it out for yourself at differenttimes of the day.

Comments

[ancienthart]

In the Southern hemisphere, swap the instructions for the 12 o'clock mark and the hour hand to find North.

[rmkratos]

[rmkratos]

[Olagio]

Super!

[Stew2]

Super handy to know this, and it even works if you don't have a watch with hands. As long as you know what time it is you can draw (if you have a pencil or something) a rudimentary watch face and then aim it's hour hand at the sun (since you know the time, you know where the hour hand would be). Do your line bisection and your golden! :D

[gvinay]

just awesome

[manwood]

That is really useful thanks

[VentureScout]

Glad to be a help, more navigation tips coming soon!

[DPeleg]

It works wonderfully, and to discover the hour (I usually have a general idea of the north) all you need to do is this:

Stp 1: Face north (if you have lost the general idea of north, you cannot do this)

Stp 2: Imagine a 24hr clock, who's center is twice your height behind you and 12 o'clock directly in front of you.

Stp 3: the dial your shadow points to is the hour!

You may need to practice is a bit.

[samalert]

It confused me a bit.
1. Does the green line always perpendicular to shadow or it should always pass through 12Oclock.
2. What if hour hand pointing 9Oclock how would the calculation be.

If 12Oclock is not the issue then why do we need clock then its always 45degree from shadow ?

I am very interested in knowing it !

[VentureScout]

Hi
samalert,

Sorry for
the confusion.

1. The ‘green line’ always passes
   through 12 O’clock position.
   
2. O.k. this is a little tricky,
   before noon you measure the angle created between the hour hand to the 12
   O’clock, in a clockwise direction. After noon you measure the angle between
   the hour hand and 12 O’clock in an anticlockwise direction.

We will use the example of 9 O’clock:

At 9 am, we make an angle from the hour hand to
12 in a clockwise direction (9,10,11,12). This gives us a 90 degree angle, so
South is at 45 degrees, half way between 10 and 11.

At 9 pm, we make an angle from the hour hand to
12 in a anticlockwise direction (9,8,7,6,5,4,3,2,1,12). This gives us a 270
degree angle, so South is at 135 degrees, half way between 4 and 5.

I hope this clears it up for you, but the best
way to understand this is to go outside and try it out for yourself at different
times of the day.

Thanks for the comments.

[the_mini_guy]

I made the following Instructable of my son's Cub Scouts project for the same technique. https://www.instructables.com/id/EVWGPBOHSBWPUIZ/?lang=en

[Ganoderma]

1. As the instructable actually explains, it goes through 12 O'clock on the watch.

2. I think the instructable forgor to include that the side that you have to use depends on the time of the day.

At 9AM the south will be at 10:30 (left side of the watch) (so north at the right side)

At 9PM the south will be at 4:30 (right side of the watch) (so north at the left side)

This seamlessly transfers over as your hour hand passes 12 O'clock.

[shilohjim]

The sun isn't shining at 9PM where I live. Just sayin' :)

[Xthinker]

What if it is 9AM?

[kenralph]

remember to adjust for British summer time/daylight saving time!

[VentureScout]

Kenralph
you raise a good point I forgot to mention. Yes you do need to adjust for
daylight savings time and/or any other local/cultural factors. It will also
depend on where you are in the ‘time zone’, because there could be a difference
of 30 degrees from one side of the time zone to the other (the distance the sun
moves in 60 minutes). This is intended as a survival skill to be used if you
have no other way to find north/south as most time it will be a few degrees
off. I would suggest experimentation, using this method and checking with a
compass and adjusting the method for your area (but be carful the watch doesn’t
affect the magnetic compass).

I will do
more instrucables for finding north using the sun, ones that aren’t affected on
time zones!

Thanks for the comments.

[mwm2929]

I dont think you physically move the numbers around on your watch face for daylight savings...lol

[kenralph]

haha! think about it...mwm2929 one day the hour hand is pointing in one direction, the next day you are 30 degrees out. the sun doesn't move, you have to adjust the direction of the hour hand