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How to use a watch as a compass
- kije 4y agoI love this trick. You can also do this using your hands if you know roughly what time it is. For example, if it's sunny out, place your arm in your shadow, parallel to the ground. Keep it there. This arm represents the current time (say, 10 O'clock). Look at your shadow and point your other arm out, parallel to the ground, and adjust it until the arm's shadow points at "12 O'clock" relative to your first arm (in your shadow). Clap your hands together, and you're pointing north!
- soperj 4y agoYou'd be pointing South no? Or is this for the southern hemisphere?
- kije 4y agoCompare it to the parent article and you'll see what I mean. If you are the center of the watch and you put your hand in your shadow, it will face the direction opposite of the hour hand in the article. If you adjust your other hand to face 12 O'clock relative to that hand, it would be at 6 O'clock if you're going by the article. So the direction is flipped. When you clap your hands together, you'll be facing North instead of South.
- deleted 4y ago[deleted]
- zmgsabst 4y agoDoesn’t N or S reverse at noon? Imagine (for simplicity) that we have 6a to 6p with solar noon at 12p. Then if I put my right arm in my shadow at 6am and my other arm 180 degrees from it, then I’ll be facing South. If I do the same thing at 11 am, I form a big wedge with my right arm on the NW side, again facing South. But at noon that changes: the sun is directly South from me, so my right arm is North and my other arm is in the same spot, so I turn around to face North. From there, my right arm is on the NE side, and my left arm makes a widening wedge as I face North — until at 6pm, I’m standing with my right arm facing East and my left arm opposite it, facing North.
- HillRat 4y agoYes -- the article doesn't explain this, but in the morning you use the clockwise side of the hour hand to find south, and in the afternoon the counter-clockwise side (IIRC).
- mckeed 4y agoIt doesn't work at 6:00 unless you know which way to face. At 11am you should have a small wedge, and your left arm should be in the shadow, in order to not point both arms straight behind you. At 1pm your right arm will be in the shadow for the same reason, so you're still facing north.
- deleted 4y ago[deleted]
- bigiain 4y agoAt sunrise or sunset, it's pretty obvious which way east or west is. At least to a first approximation. For a second approximation you'll want to interpolate between the equinox and solstice and use that to approximate an allowance for the ~24 degree tilt of earths rotation axis. That second approximation error is there for all times that are not midday, but reduce to zero as you approach midday. A third approximation might be to allow to the offset between your local timezone and solar midday. Where I am (Sydney) we are fairly close to the middle of the +10 and +11 timezone boundaries, so solar noon is within a few minutes of timezones noon. Perth on the other hand is way out to the west of it's timezone, so solar noon there is almost 25 minutes off from timezone noon. So "watch north" in Perth will be about 7.5 degrees off "true north".
- b3morales 4y agoI had a watch with a bezel like this as a kid, but over the years I'd forgotten how this technique worked. A nice refresher!
- AdmiralAsshat 4y agoIs that what the rotating dial on my watch is for?
- Xylakant 4y ago> Positioning the rotating bezel so that it points south, will then allow you to read other approximate compass directions.
- tomjakubowski 4y agoAlso for measuring durations.
- owlninja 4y agoLikely more for this: https://www.citizenwatch-global.com/support/exterior/measurement.html https://www.citizenwatch-global.com/support/exterior/measure...
- askvictor 4y agoFor SCUBA diving, it is to tell you how long you've been underwater for, so you can determine (among other things) your nitrogen saturation. I'm not sure if the original design was specifically for that purpose, but every (dial-based) diving watch has such a ring.
- thrdbndndn 4y ago>I'm not sure if the original design was specifically for that The rotating dial (I'd rather call it bezel) literally has NSEW and degrees on it, it can't be original for counting time in diving.. Or maybe you're talking about different types of dial here?
- frankus 4y agoDon't forget to subtract an hour if you're on daylight saving time.
- tejtm 4y agoand your offset within your time zone
- quickthrower2 4y agocross reference with a reliable compass too!
- politelemon 4y agoCarry a copy of tzdata with you just in case!
- deleted 4y ago[deleted]
- praptak 4y agoDaylight saving messes this up a bit.
- askvictor 4y agoProbably not any more than big timezones do.
- throwaway4837 4y agoIsn't this just using the sun as a compass? You could easily just look at the position of the sun knowing what time it is, or use your hand and make a sun-dial. I believe the watch is only there to tell us the time and cross reference that with the sun's position.
- Terr_ 4y agoYeah, the strategy only really involves (A) knowing the current time and (B) a protractor or a good sense of angles. Or in word-algorithm form: 1. When the sun rises that's usually at 6AM in the East, at 12AM noon it's usually towards the South, and when it sets that's usually 6PM in the west. (Valid for northern hemisphere only.) 2. Use the current time to linearly interpolate between those three values. 3. Once you know the heading of the sun, you can figure out which way is north.
- rosywoozlechan 4y agoRight, if you can see the sun and know the time of the day why do you need a watch for this.
- re 4y agoIt would be fascinating to see a visualization of how the accuracy of this method varies given parameters like latitude, time of day, time of year.
- madcaptenor 4y agoDon’t tempt me, I have real work to do.
- kQq9oHeAz6wLLS 4y agoI bet that real work will still be there tomorrow...
- quickthrower2 4y agoAnd local/national government politics (aka stuffing around with daylight savings and carving out new time zones)
- recasfoin 4y agoIf it's summer solstice and you're on the equator and it's noon, then the accuracy is bad. Otherwise, YMMV -- (literally!) https://academic.oup.com/astrogeo/article/52/3/3.12/187095 https://academic.oup.com/astrogeo/article/52/3/3.12/187095
- xcambar 4y agoIf I know the time and see the sun or shadows, I approximate the direction by estimating the course of the sun. It always works significantly well, meaning I never need it on critical situations and the margin of error is bearable. But I'm mostly surprised not to see someone else comment the technique before. Is it not a known technique?
- uoaei 4y agoOf course what you describe is the main way people navigate by the sun, when the margin of error is bearable. In more extreme situations where precision is needed, decimating the margin of error is pretty important, especially when used in conjunction with a map or known landmarks.
- Nition 4y agoSouthern Hemisphere version: Instead of pointing the hour hand at the sun, point the twelve o'clock at the sun. North is approximately half way between the hour hand and the 12.
- gowld 4y agoOr use a Southern Hemisphere watch that spins the hands in the Australian direction.
- mordechai9000 4y agoThis is a good way to get a general idea, but unless your local solar noon happens to coincide with noon on your watch, it's going to be off. For instance, solar noon at my current location is around 2:00 pm. As long as the sun is out, it's a good way to stay oriented and keep to a general heading. It works well when combined with local features and topography. So you can say something like "I'll keep heading more or less south until I see the river, then I know I can follow it upstream to the bridge and intersect the road back to my car."
- system2 4y agoIf I see the sun, why would I need a watch to tell me where south is?
- certifiedloud 4y agoonly because you'd need to know what time it is to know where south is relative to the sun.
- usrusr 4y agoDepends: are you the kind of person who considers it a good idea to be aware of uncertainty? You'll be perfectly happy with "I'm on the northern hemisphere, it's afternoon, so south must be somewhere left of the sun". But if you are the kind of person who like to lose themselves in point-something percentage point deltas in small (or unknown) sample size market research, go on, pat yourself on the shoulder for building that makeshift shadow observatory, it will make you happy even if you don't really know where exactly you are relative to the center and natural bounds of you time zone.
- dctoedt 4y agoAn old Boy Scout trick.
- politelemon 4y agoWouldn't this be messed up on longer days, like in summer when the sun rises at about 4 AM and sets at 9PM? Or similarly, winter when the days are really short
- mckeed 4y agoYes, at 6:00 you have to know which side to put north and south, and from 6pm-6am it will be North instead of South between the hour hand and 12. If you know the sun rises in the east, though, you can account for that and the trick can still be helpful.
- kqr 4y agoNo. Earth still makes a full rotation in 24 hours, at a fairly constant angular velocity. The only thing that changes during longer days is the height of the sun over the horizon, not its angle along the surface of the planet.
- politelemon 4y agoAh understood thanks
- TobTobXX 4y agoNo, fo the same reasons sun dials still work: The sun rises at a slightly different point on the horizon. The trick even works north of the polar circle where there may be 24h days, as the sun is always in another direction. The sun moves around, whether it is above or below the horizon, so the trick works regardless of length of time the sun happens to be above the horizon.
- codeflo 4y agoFrom some of the comments, I’m not sure people fully get this. It’s basically doing a geometric construction of the sun’s path across the sky, using the distance between the hour hand and the 12 on the watch face as one of the input angles in the calculation. That’s quick (important because you have to repeat it while you’re marching) and easy to remember (also important because you might need it in a situation without access to Wikipedia). Under the assumption that the sun rises at 06:00 in the exact East and sets at 18:00 in the exact West, the construction is almost perfect. Of course, that’s never exactly true in real life, but still a lot more accurate than “well I know the sun is roughly South”.
- dheera 4y agoYou'd also need a 24-hour watch, as the sun makes a full 360 in 24 hours, not 12 hours.
- fiddlerwoaroof 4y agoThis just means you go halfway between the hour hand and the 12 marker.
- bigiain 4y agoAustralian checking in. for the second time this week I'm commenting that your US/Northern Hemisphere sun goes THE WRONG WAY for my internal navigation instincts... The sun is currently about NNE as I write this.
- est 4y agoYou don't need to remember the method, you can deduce it from two simple facts: 1. In a perfect world, 12 o' clock is where sun at its highest peak in the sky, 24 o' clock is where sun below the horizon at its lowest. 2. If your are in northern hemisphere, the sun's trajectory is slightly off to the south. Now try emulate the sun's rotation with your watch's hour hand.
- TheRealPomax 4y agoThe word "deduce" is doing a lot of heavy lifting here.
- bigiain 4y agoMeh. If you know the trick exists, you can derive it from first principles, which for some people (me included) is a much easier "trick" than accurately remembering the exact steps/process for something like this. Maybe there's a important semantic difference between derive and deduce? But I totally agree with the grandparent poster.
- vesinisa 4y agoThis trick alone is why I think if daylight saving time is ever abandoned we should switch to permanent winter (~natural) time.
- politelemon 4y agoAgree for different reasons - working in tech in the UK, it would just match UTC and make life easier.
- tmtvl 4y agoDoesn't work quite as well with a digital watch.
- marktolson 4y agoI hope this is a joke.
- madcaptenor 4y agoEssentially this means approximating the bearing of the sun X hours after midnight the sun as 15X degrees. This works better the closer to the poles you are and the closer to the winter solstice it is - see for example https://possiblywrong.wordpress.com/2012/01/25/using-a-watch-as-a-compass/ https://possiblywrong.wordpress.com/2012/01/25/using-a-watch...
- pwillia7 4y agoI'm more impressed with someone using it to determine the favored starting line for their yacht race. https://www.citizenwatch-global.com/support/exterior/yacht.html https://www.citizenwatch-global.com/support/exterior/yacht.h...
- Kon-Peki 4y agoThere are usually going to be too many other factors at play to use this to your advantage at the start, but occasionally you’ll see someone start a race on a completely different tack than the rest of the field and go on to finish far ahead of everyone else. Edit - to be clear, almost everyone figures out and starts on the favored tack - you don’t really need a sailing watch to do this. In races with heats or starting groups, you have to do this 10-15 minutes before your start, because once the starting sequences begin you don’t get near the start line until it’s your groups turn. So the advantage comes from recognizing and adjusting to any wind shifts that may have happened in the few minutes before your race.
- bigmattystyles 4y agoI learned this from Gallipoli (1981 Peter Weir movie about WW1). In the movie they get totally screwed by this trick when it turns out it’s overcast. Tangent, that movie is great, the synthesizer music is odd but to me it works and the whole movie is beautiful.
- riversflow 4y agoMy parents showed me that movie when I was maybe 9 or 10 and getting that boyish fascination with war (amongst a few other war movies like Das Boot). I didn’t understand the colonial subtext of the movie, which made it that much more impactful. It has absolutely stuck with me, both in terms of the absolute insanity of warfare, but also just how life in general can be a complete tragedy.
- psychphysic 4y agoThis is a great trick and with practice you don't even need a watch, heck you don't even need an object to cast a shadow. The sun is over there, a shadow would be that way, it's about 5 o'clock. That must be north! What I've always thought of as witchcraft is this. Jab a stick in the ground, mark the end of the shadow. Come back some time later say 15-30mins. Mark the new end of the shadow. Draw a line between marks and that is an east-west line! In the Northern hemisphere the stick is south of that line, in the southern hemisphere it's North! What!!
- chrisseaton 4y ago> The sun is over there, a shadow would be that way, it's about 5 o'clock. That must be north! That works for example if you have a path and you're trying to find out which way goes north and which south, but a watch can give you an actual quantifiable bearing that is actionable if you have no other ground orientation.
- CSSer 4y agoNormally an upvote is enough but I just have to say that your enthusiasm about this made me smile so wide. This is great.
- bombcar 4y agoYou’ll love Jeremy Tan - https://youtube.com/c/JeremyTanMagic https://youtube.com/c/JeremyTanMagic Read that whole thing in his voice having seen the end.
- sverhagen 4y agoOh boy, I got sucked into those shorts real hard. How the hack (heck) does he guess the card those people on the street seemingly all by themselves picked?
- bombcar 4y agoIt’s a rabbit hole but you can find some of the tricks online - you either do slight of hand, control the card picked (a force), or you control the card once in the deck. Combining them and being really good at it is what makes it “what”! https://youtube.com/c/Jasonmahermagician https://youtube.com/c/Jasonmahermagician Is another one I enjoy and he has longer videos showing some of the tricks.
- ww520 4y agoAh. This is the Boy Scout trick learned when was a kid.
- gonzo 4y ago1959 edition of the Boy Scout Manual "Time for North" https://mediafiles.scoutshop.org/m2pdf/BePrepared_Vol_3_No_9.pdf https://mediafiles.scoutshop.org/m2pdf/BePrepared_Vol_3_No_9...
- quickthrower2 4y agoFun but probably useless as an actual compass for navigation with maps which requires higher accuracy.
- ottoflux 4y agoYou can do this (crudely but effective enough) with a any watch if you take a second to make a simple sundial. Rotate it with the stick (or whatever) until the shadow reflects the actual time and you’re pointing North (in the Northern hemisphere). It helps to be familiar with the angle range of how time is broken up in the day on a sundial but it works.
- nevster 4y agoDon't forget to flip it if you're in Australia! Half-way between 12 and hour hand is North.
- anonu 4y agoIf you dont know what time it is - maybe just wait until the sun gets close to setting? Adjust a bit for summer/winter...
- throwaway14356 4y agocall soneone!
- Ylpertnodi 4y agoHow to do it under cruise missile pressure https://www.reddit.com/r/UkraineWarVideoReport/comments/u79dwy/malcolm_nance_during_missile_strike/ https://www.reddit.com/r/UkraineWarVideoReport/comments/u79d... about 38 seconds in.
- lostsock 4y agoVery impressive reaction from the guy in the video, but I don't think he's using this to tell the heading. It looks like he also has a compass on his watch band as you can see at 1:03.
- nicbou 4y agoI learned this trick a while ago. Its simpler form is even more useful: the sun traces an arc from east to west, and is south at noon. This gets you a rough idea of where North is. Do it often enough and it becomes instinctual. You keep your bearings so long as the sun is up. This is useful if you don't want to constantly check your phone.
- perilunar 4y ago> and is south at noon As long as you are north of the Tropic of Cancer.
- schoen 4y agoAnother useful thing to know: in the northern hemisphere, satellite dishes point south. In the southern hemisphere, they point north. This is because geostationary orbits (where satellites that communicate with fixed satellite dishes are located) are all above the equator. https://en.wikipedia.org/wiki/Geostationary_orbit https://en.wikipedia.org/wiki/Geostationary_orbit So, these dishes are aimed at a point above the equator (possibly with some eastward or westward component, but mainly southward).
- hunter2_ 4y agoAnd the angle they point up is (very roughly) the inverse of the latitude. A dish near the equator (0 degrees latitude) points 90 degrees up, a dish near the pole (~80 degrees latitude) points 0 degrees up (tangent line), a dish halfway between there and the equator points about 45 degrees up, and so forth. Page 122 has a handy table with the more precise+accurate lookups (shifted away from the pole since the satellite's altitude is quite a bit shy of infinity, at 35,800km): https://www.ngs.noaa.gov/CORS/Articles/SolerEisemannJSE.pdf https://www.ngs.noaa.gov/CORS/Articles/SolerEisemannJSE.pdf
- perilunar 4y agoThat's true for dishes where the feed horn/antenna is inline with the dish axis. A lot of smaller satellite dishes nowadays use off-axis feeds. But you can do a bit of mental geometry to adjust.
- defrost 4y agoAssuming they're communicating with a geostationary sat of course - and the vast majority of sats these days just aren't (Starlink constellation being an obvious example of thousands). Even the quote from the wikipedia article [1] is dubious: > Weather satellites are also placed in this orbit for real-time monitoring and data collection as many weather and climate satellites are on near earth polar precession orbits to rapidly scan (obit time between one and two hours) a full circle about the planet for a full picture. [1] https://en.wikipedia.org/wiki/Geostationary_orbit https://en.wikipedia.org/wiki/Geostationary_orbit
- hyperhopper 4y agoWhich way is it when it's 6 o clock then? It could be either direction! If I wake up from a stupor I wouldn't know if it's morning or nighttime.
- madcaptenor 4y agoWait a bit. If it gets brighter, it's morning; if it gets darker, it's night.
- Maursault 4y agoIn the event of overcast sky, apparently there is a way to accurately determine the Sun's position within a few degrees.[1] [1] https://en.wikipedia.org/wiki/Sunstone_(medieval) https://en.wikipedia.org/wiki/Sunstone_(medieval)
- riversflow 4y agoBut if I’m gonna carry a sunstone, why not just carry a small compass. Also, a sunstone won’t help you if the sun is obscured by terrain or trees.
- Maursault 4y agoIt's a different application, and there are no trees or terrain on the ocean. The sunstone reveals the position of the Sun when the sky is overcast, and from the position of the Sun one can not only determine direction, but also time of day. If there is a way to use a compass to tell the time of day and the position of the Sun when the sky is overcast, I'd love to learn it.
- riversflow 4y agoWell the OP is about using a watch to find North. As I understand, a sextant can be used with a nautical chart, a compass and an accurate time keeper to find position, as long as a horizon can be found and you have an idea of your latitude. While a cool viking discovery, they aren’t really practically useful.
- Maursault 4y ago> Well the OP is about using a watch to find North. False, or at the very least this description is incomplete. OP concerns using a watch and, critically, the position of the Sun to determine cardinal directions. If the Sun can't be located, the exercise is pointless. > As I understand, a sextant can be used with a nautical chart, a compass and an accurate time keeper to find position, A sextant is used to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. If the sky is overcast, a sextant is useless. Earth's skies are cloudy, and at any time 67% of the Earth's surface is typically covered by clouds, and this is especially true over the oceans where less than 10% is entirely clear of clouds.[1] But in the case of having a sextant, nautical chart and a time keeper, under overcast skys, the sunstone can replace the compass and permit the function of the sextant, and one would still be able to find position under overcast skies that would be impossible without the sunstone and with a compass. > as long as a horizon can be found This is not a given as weather rarely cooperates. Fog is a common occurrence on the ocean, and it will conceal the horizon. > and you have an idea of your latitude. I'm pretty sure those 4 items are all that is necessary to determine latitude. > While a cool viking discovery, they aren’t really practically useful. As explained above, on the ocean, cloud cover ordinarily obstructs the position of the Sun. So a sunstone is practical under common conditions on the ocean of skies obscured by cloud cover. [1] https://earthobservatory.nasa.gov/images/85843/cloudy-earth https://earthobservatory.nasa.gov/images/85843/cloudy-earth
- MarkMarine 4y agoThis is a great trick, but they leave out the rest. At least give people a link to learn how to use a compass and map together. I suppose walking in a general direction is good, but learning how to read a map, orient, triangulate your position, take a bearing, then travel that direction is a super valuable skill if you're ever in a situation that you actually need to know how to use your watch as a compass. https://www.rei.com/learn/expert-advice/orienteering-basics.html https://www.rei.com/learn/expert-advice/orienteering-basics.... http://www.learnorienteering.com http://www.learnorienteering.com
- NonNefarious 4y ago
- perilunar 4y agoIt's a shame really that most watches are 12 hour time. With a 24 hour clock (with noon at the top/midnight at the bottom) the hour hand tracks the Sun and North is at 12. And it's obvious enough that you don't even need to remember how it works. In the Southern Hemisphere you need a clock that goes anti-clockwise (or you can mentally flip it). See: https://sunclock.net https://sunclock.net
- 23B1 4y agoI've been to-and-fro across much of North America for much of my life. I have never encountered a situation where it was especially challenging to orient to the cardinal directions in a few minutes using a few basic clues; how trees and plants orient, satellite dishes, how houses are oriented, the stars, the time of year and the subsequent location of the sun, how streets are planned, named & numbered. Even a cursory glance at a map can help you identify major terrain features that can help you orient. Have never had to resort to these methods of using a watch or a magnetized needle, because waking up in in the middle of a mysterious jungle is a pretty rare event ;)
- Normille 4y ago>I've been to-and-fro across much of North America for much of my life. I have never encountered a situation where it was especially challenging to orient to the cardinal directions... This is one thing I always find quite odd on American TV / Films. People [eg. police pursuing someone] will inevtiably say something like "He's turned north onto 21st St." or "He's heading east on 12th street". I always wonder how they know the compass direction. I don't think many people in Britain would express directions like this, using compass points, or even know which direction was which. Do US streets have the cardinal directions on the roadsigns, or are you all issued with built-in compasses at birth?
- chimeracoder 4y ago> Do US streets have the cardinal directions on the roadsigns, or are you all issued with built-in compasses at birth? A lot of cities have somewhat gridlike street patterns, and those are often roughly oriented to the cardinal directions, so in those places, people will use them that way. (This is especially true in cities that are relatively flat and were mostly settled by colonists after the mid-19th century. Look at a map of Pierre, SD, Denver, CO, or Wichita, KS.) Even when it's not north-south, people will still do this. In Manhattan, for example, the streets are actually offset by 29°, but people will still say "east" or "west" to mean "towards the Hudson/East River", respectively. But also, the dialogue in cop dramas is always going to be forced and artificial, so I wouldn't read too much into that anyway.
- Razengan 4y agoSomething I was just wondering about recently: If the earth's magnetic field (and other similar "passive" global effects) can be sensed enough to move a compass needle, can it be used to power low-energy devices? Like could we ever have always-on displays (like 0.00001 FPS, 10x10 pixels or whatever) or whatnot that are powered by the planetary magnetic field?
- thombat 4y agoSadly it's not enough to have a force; it needs to produce a motion (to perform work). Think of the analogy with a ball feeling gravity at the top of a hill: it has the potential to release energy but it remains unrealised until it starts rolling downhill. Once in motion energy can generated, say by coupling it to a dynamo, but once the ball is at rest at the bottom then even though it still feels gravitational attraction there is no power output.
- DeathArrow 4y agoStep 1: Put a stick in the ground. Step 2: Look at the shadow. Step 3: ??? Step 4: Profit!
- haroldship 4y agoThis is great! I have a Seiko Alpinist SARB017 that works exactly this way
- hsuduebc2 4y agoSo basically sun is always south? Why exactly do I need watches?
- mcv 4y agoNot if you're in the southern hemisphere, but your watch isn't going to tell you that.
- mcv 4y agoIt's nice that the explanation starts with this disclaimer: > Keep in mind that these determinations are approximate as there is some discrepancy at different latitudes and in different seasons. But it doesn't explain that this only works on the northern hemisphere, and in summer only if you're well above the tropics. Near the equator, this isn't going to work at all, and on the southern hemisphere, everything needs to be reversed. It's a cool trick, but I think just understanding the relationship between the earth and the sun is easier and more universally applicable.
- GekkePrutser 4y agoI've not had a watch with hands for decades. But my smartwatch has a compass function built in :)
- baronblackmore 4y agoHow is the sun going to be in the same place at 4am and 4pm.
- ChrisMarshallNY 4y agoI learned this, when I was a kid (and have long since forgotten it). These days, I tap the Compass complication on my Apple Watch...
- tolger 4y agoThis is a very cool use for a watch. You can use any watch, but some watches, like the Seiko Alpinist, even have a rotating bezel with the compass points. This makes it a lot easier to find the other directions. One thing the article forgot to mention, is that the trick works only for standard time. If you are on daylight savings time, the direction will be off.
- wkjagt 4y agoThis reminds me of my father showing me as a kid: if I hold my watch exactly in this position in relation to the sun, and look at it from this exact angle, I can tell exactly what time it is.