How to find true north not magnetic north?

[gary350]

How to find true north vs magnetic north? Online information says magnetic north moves around as much as 2.5 degrees. Lots of information online about true north 1 place save 5 degrees off magnetic, another place says 10 to 12 degrees, another place 10 to 25 degree, another place 15 to 30, another place says true north is 45 degrees from magnetic north. Another place says true north lines up perfect with the north star all calculations are taken from the north star.

What I am trying to do is find out, when is the SUN is exactly straight up at my house. I used a compass to find magnetic north then hammer a steak in the ground when the suns shadow lines up with magnetic north sun it straight up with magnetic north but not with true north. Magnetic north shows sun is straight up a 1:12 pm at my house. Seems to me I read someone where magnet north vs true north is about 23 degrees but with a fluctuation of 2.5 degrees what does that really mean.

Another place I read magnet north vs true north is at maximum angle at the north pole the closer you get to the equator the lower the angle. There is so much BS online these days no one knows what to believe.

If I knew sun rise and sun set I could calculate the 1/2 point and know when sun is straight up. I do know sun rise was 5:03 am June 22 but never could find out what sun set was. I know from watching the sun it sets about 8:30 pm. Convert 8:30 to a 24 hr clock = 20:30. 5.03 + 20.30 = 25.33 / 2 = 13.34 convert back to 12 hr clock = 1.34 pm I have no clue how accurate this is. 1.34 pm is more accurate than 1:12 pm.

My zip code is 37129 there may be a place to look up information by zip code for, sun rise, sun set, high noon but I have not found it?

 

[.Scott]

True north is easy.
If you want a good approximation and you are in the Northern hemisphere, just look at Polaris, the North star. It is never more than 0.75 degrees away from due north (true north).

If you want to be more precise, look at Polaris shortly after sunset and then again shortly before sunrise. You should try to get them as close to 12 hours apart as you can (easier to do in the winter). Then split the difference.

Alternatively, you can use a GPS and follow a path where the latitude has increase and the longitude hasn't changed.

... or: wait for Polaris to be directly above or below the first star in the handle of the Big Dipper. At those times, Polaris will be due north.

 

[Dale]

This will be easier:

https://www.esrl.noaa.gov/gmd/grad/solcalc/sunrise.html

 

[Vanadium 50]

This will be easier:

This will be easier still. Since you're north of the Tropic of Cancer (your zip code does not start with 987 or 8), then sun will never be directly overhead.

 

[Helios]

You draw a circle on the ground. You put a straight-up stick in the center. The shadow will cross that circle before noon and after noon. Connecting those points will give you and east-west chord and perpendicular to that a north-south chord.

 

[.Scott]

This will be easier still. Since you're north of the Tropic of Cancer (your zip code does not start with 987 or 8), then sun will never be directly overhead.

From the description, I think he was looking for "high noon".

 

[sophiecentaur]

Why has no one suggested a simple magnetic compass and then look up the magnetic variation on an Ordnance Survey map or whatever is equivalent in the particular country? A magnetic compass is pretty convenient to use and the rest is numbers.

 

[gary350]

This will be easier:

https://www.esrl.noaa.gov/gmd/grad/solcalc/sunrise.html

I found this already. I even figured out my LN=35.8981 & LM=86.4561 but the calculator will not calculate this. Every time I click calculate it returns to the town already listed.

Finally found the option to type in my LN=35.8981 & LM=86.4561 but it changes my numbers to another location. It tells me solar noon is 10:50 am I can look at the sun and see it is 2 hours from being straight up.ln=

 

[Helios]

I predict the OP high noon for today, using longitude = 86.45610°.
------------------------------------------------------------------------------
Knowing the following;
Daylight Savings time = 1 hour = 15°
Offset from standard meridian= 3.5439° ( east )
Equation of time = 3m 29s slow = -.87083° ( for today 6/29 )
-----------------------------------------------------------------------------------------------
15° - 3.5439° + .87083° = 12.32693° = 49m 18s
the OP high noon for today = 12:49:18 pm (hr:m:s)
This agrees with NOAA within 3 sec.

 

[russ_watters]

Why has no one suggested a simple magnetic compass and then look up the magnetic variation on an Ordnance Survey map or whatever is equivalent in the particular country? A magnetic compass is pretty convenient to use and the rest is numbers.

So, right; the question is oddly put(and contains the "straight up" error), so I think people are assuming constraints based on speculation.

For me, the easiest way I can think of to find when the sun is due south is to add/subtract your angular distance from your nearest time zone center meridian.

E.G., my longitude is 75deg, 16', 27", so local noon for me is 12:06 (EST).

We could probably think of a dozen methods though.

 

[sophiecentaur]

I can't find where the required accuracy is stated in this thread. The position of Polaris is near enough for Jazz and certainly is as good as you can hope for if you don't have some optical 'help' either to find it or to use it. You can improve by a factor of about ten with not much trouble.

Astronomical telescope mounts are aligned to point to the North Celestial Pole with a Polarscope. The polariscope is a small telescope with angular magnification such that small circle has a radius of 0.75°. You look at the Big Dipper with one eye and rotate the reticle so that the diargram of the Big Dipper is orientated the same way as the real thing (not overlaid; it's way outside the field of the scope) in the eye that's looking through the scope. This only needs a little practice. You then adjust the telescope mount so that polaris sits bang in the middle of the tiny circle and the + is at the CNP.
That's not the most accurate method but other methods involve knowing your longitude and the exact time of day to rotate the reticle at the correct angle. This way uses the sky as its own clock. I was contemplating suggesting making one up yourself but the radius of that circle would be so small that you would need some magnification unless you have Elven Sight.
Note - polaris doesn't appear where you would expect the 'pointers' to point because the polariscope is an inverting scope. The image of polaris in the scopeis diametrically opposite where it is in the sky.
Acnowledgement: That diagram is what you see in a Skywatcher polariscope so I guess it could be copyrighted. The method is an improvement on the one quoted by @.Scott as it works whenever you can see polaris plus most of the Big Dipper.

 

[sophiecentaur]

For me, the easiest way I can think of to find when the sun is due south is to add/subtract your angular distance from your nearest time zone center meridian.

You would need to know your longitude for this, of course, and know about whether you need to add or subtract your angles. Astro navigation works 'upside down' if I remember correctly. (Jus' sayin' , as one who has frequently used reciprocal bearings in my navigation)
I love the Polarscope method (above) because it does all that for you.

 

[russ_watters]

You would need to know your longitude for this, of course...

Fortunately we all carry a device that can tell us.
(of course, there is probably an app for telling local noon too)

and know about whether you need to add or subtract your angles.

Gawd, I would hope most people can figure that out!

 

[sophiecentaur]

Gawd, I would hope most people can figure that out!

You'd be surprised. It's as difficult as reverse parking into a bay and that's beyond a lot of people.
How many transatlantic family telephone calls have been made five hours early when they would have been five hours later? (Not me, of course!)
Edit: And, of course, that great Astronomical Thing in your profile pic gives it all away about you.

 

[tech99]

To find True North exactly for surveying new microwave stations, I used a Sun sight taken with a theodolite. I then used Birdwood's Tables (probably no longer exist), which gave the Sun's azimuth for every second of every year.
I notice that Stanford's Astro Navigation Tables, a small, current publication, give the time (near noon) when the Sun (or any navigational star or planet) is on the N-S line of the Greenwich Meridian, and this will probably enable N-S to be found elsewhere.

 

[sophiecentaur]

To find True North exactly for surveying new microwave stations, I used a Sun sight taken with a theodolite.

What sort of angular precision do you have to work with? The Sun is very handy because it's there during your working day but it is not very co operative as it wanders all over the sky.

 

[Dale]

Every time I click calculate it returns to the town already listed.

In the drop down for the town select “Enter Lat/Long”

 

[gary350]

https://www.esrl.noaa.gov/gmd/grad/solcalc/sunrise.html

This link gave me wrong information using my zip code.

I used my car GPS to find N35 52.802 W086 27.684

I typed the GPS information into Google Maps and it shows me where I am standing holding the GPS in my driveway.

Now that I know this is correct N35 52.802 W086 27.684 I type in into the above link and it tells me solar noon is 10:50am which is wrong by 2 hours. Sun is almost straight up now at 1 pm. I don't have time to set things up in 10 minutes to check high noon with the compass again. Last time I check the compass said high noon was 1.12pm which is only off by 22 minutes according to another persons solar noon calculations.

Tomorrow I could set up the experiment in the yard again. I can measure the angle difference between the 12:50pm shadow vs 1:12pm shadow. Measuring the shadow is not 100% accurate but close enough I could be off by 1 minute. Once I know the angle between solar noon at magnetic noon I can always subtract from magnet noon to find solar noon. .

 

[Dale]

which is wrong by 2 hours.

Did you set your time zone and daylight savings correctly? It works for me.

 

[gary350]

I set up a quick test, metal rod stuck in the ground at 45 deg angle. Time 22 minutes from 1:21 pm to 1:42 pm the sun shadow moved 6.5 degrees. OH wait I screws up I only timed it 21 minutes. OH well do the math. Math says shadow movement is 6.8 degrees for 22 minutes.

I am still not 100% sure the difference between magnet noon and solar noon is 22 minutes?

According to Sun Dial online information sun shadow movement gets bigger & bigger as the sun gets closer to the horizon.

The best time to do this test again tomorrow would be from 12:50 pm to 1:12 pm from the experiment I just did sun movement should be slightly more than 6.8 degrees because sun is closer to 90 degrees..

 

[Dale]

Hopefully sometime before tomorrow you can get the noaa calculator working :-)

 

[gary350]

Hopefully sometime before tomorrow you can get the noaa calculator working :-)

I finally figured out how to use noaa. These numbers are correct for GPS & Google Maps but not for noaa N35 52.802 W086 27.684

N & W & 0 need to be dropped. The . needs to be moved 2 places to the left for noaa.

N35 52.802 = 35.52802 = Longitude

W086 27.684 = 86.27684 = Latitude

DST has to be clicked

Do not change time zone number -6

Magnetic noon = 1:12 pm

Solar noon = 1:18 50 pm

Shadow movement angle from magnetic noon to solar noon is 6.8 degrees

 

[russ_watters]

I finally figured out how to use noaa. These numbers are correct for GPS & Google Maps but not for noaa N35 52.802 W086 27.684

N & W & 0 need to be dropped. The . needs to be moved 2 places to the left for noaa.

N35 52.802 = 35.52802 = Longitude

W086 27.684 = 86.27684 = Latitude

DST has to be clicked

Do not change time zone number -6

Magnetic noon = 1:12 pm

Solar noon = 1:18 50 pm

Shadow movement angle from magnetic noon to solar noon is 6.8 degrees

I get 12:46pm CDT by my previous calculation. The link tells me 12:50 CDT. As a cross-check, "the equation of time" of 4 minutes is the deviation, which matches the difference between the calculations (I didn't realize the deviation due to Earth's orbit was that much).

So I think you are doing at least two things wrong:
1. When separated by one space each, the position measurements are degrees and minutes. NOAA wants degrees, minutes and seconds. You have the degrees and minutes already, and just need to convert the seconds by multiplying the decimal of minutes by 60. Or just omit seconds because it makes very little difference.

2. I don't know what the other error could be. The date maybe? Since the center of your time zone is 90 degrees, you are east of it, which means local noon is usually earlier, not later than what your clock tells you (DST adjusted).

 

[gary350]

I should check magnet north again. I have learned a very good expensive compass will give a screw up reading in town it is so sensitive it picks up nails in the yard, metal car in the driveway 50 ft away, metal in the house, metal utility in the yard, chain link fence around the yard, etc. A cheap $1 toy compass is more accurate in town because near by metal things do not effect it.

 

[Vanadium 50]

A cheap $1 toy compass is more accurate in town because near by metal things do not effect it.

That's not possible. A compass measures a magnetic field. There is one magnetic field at each point in space, not multiple ones depending on whether nearby objects "count" or not.

 

[tech99]

You can point the hour hand of a watch at the Sun, then split the angle between the hour hand and 12 o'clock, and that is True South.

 

[gary350]

That's not possible. A compass measures a magnetic field. There is one magnetic field at each point in space, not multiple ones depending on whether nearby objects "count" or not.

Metal attracts magnets. Compass needle is a magnet. Car is metal, chain link fence is metal, nails are metal. The cheapo compass is a magnet it does not point in the direction of metal. The expensive compass is a better magnet it will find everything metal in the yard & house you can not get a accurate reading unless your out in the wilderness where there is no metal. Buy a compass see for yourself.

 

[Vanadium 50]

None of what you wrote is correct.

 

[cosmik debris]

You can point the hour hand of a watch at the Sun, then split the angle between the hour hand and 12 o'clock, and that is True South.

Hour hand? All I see are numbers.

Cheers

 

[phyzguy]

If you go to the website below and enter your location, it will tell you the time of local noon. Drive a vertical stake in the ground, and at local noon, its shadow points to true north.

https://www.timeanddate.com/astronomy/solar-noon.html

 

[sophiecentaur]

You can point the hour hand of a watch at the Sun, then split the angle between the hour hand and 12 o'clock, and that is True South.

Actually, it isn't unless you happen to be in the centre of a time zone. Your watch shows Universal time (plus or minus the appropriate hours offset) so there can be up to 180/24 = 7.5 degrees of error with that method. Near enough if you're lost out on the moors but not if you are trying to build a house or draw an accurate map.

 

[gary350]

None of what you wrote is correct.

Prove it.

 

[Vanadium 50]

You were the one who claimed that some compasses measure different magnetic fields than others. Apart from going against several centuries experience with magnetism, it is contrary to all good sense and logic. So it seems to me the burden is on you to prove your iconoclastic and heterodoxical beliefs, not mine. (However, before you go down that path, I recommend you review the PF Rules on personal theories. Wouldn't want to have it removed as crackpottery, would we?)

A compass is a device to measure the direction of the local magnetic field. The local magnetic field has one value, with one direction. It does not have multiple values depending on the imputed presence or absence of various nearby objects. That would be like having two thermometers, one that tells you the temperature of the room with the air conditioning on and another with the air conditioning off. Instead, a thermometer measures the actual temperature in the actual room, and not the imagined temperature in some speculative room. A compass does the same thing - it measures the real magnetic field, and not some imaginary field for some counterfactual arrangement of nearby objects.

 

[berkeman]

Compass needle is a magnet.

True, but a weak and very small one. Unless you get real close to some ferrous material, the magnetic attraction between the compass needle and the object will have basically no effect.

But it's true that ferrous objects do deflect the Earth's magnetic field nearby. That's why it's hard to find a good place to mount a compass in a typical car made of steel.

https://i2.wp.com/mumetal.co.uk/wp-content/uploads/2013/10/Picture1.jpg

 

[Nugatory]

Metal attracts magnets. Compass needle is a magnet. Car is metal, chain link fence is metal, nails are metal. The cheapo compass is a magnet it does not point in the direction of metal. The expensive compass is a better magnet it will find everything metal in the yard & house you can not get a accurate reading unless your out in the wilderness where there is no metal. Buy a compass see for yourself.

This isn't quite right. A compass points in the direction of the magnetic field at wherever the compass is located. Nearby metal objects do affect the direction that the compass points, but not because they attract the needle; they change the direction the magnetic field in their vicinity points.

The difference in readings between a cheap compass and an expensive one has nothing to do with one being better than the other at finding nearby metal. They're both reading the exact same magnetic field because there's only one magnetic field at each point in space; the expensive one is just doing it better (more accurately and more repeatably).

And all of this reminds me... we just replaced some stuff in the console of the boat, and the added metal is affecting the local magnetic field differently than what had been there... so in the next few days I have to slightly adjust the compass housing so that it reads zero degrees when I'm going due north. Because it's the 21st century I'm not going to use Polaris to determine north, I'm going to use the GPS - head out to open water, drive due north according to the GPS, adjust the compass so it agrees. And why am I messing with a compass at all when I have GPS? Long before I had a GPS I would get through the fog by following a compass heading from buoy to buoy and I want the backup in case the GPS dies on me.

 

[gary350]

You were the one who claimed that some compasses measure different magnetic fields than others. Apart from going against several centuries experience with magnetism, it is contrary to all good sense and logic. So it seems to me the burden is on you to prove your iconoclastic and heterodoxical beliefs, not mine. (However, before you go down that path, I recommend you review the PF Rules on personal theories. Wouldn't want to have it removed as crackpottery, would we?)

A compass is a device to measure the direction of the local magnetic field. The local magnetic field has one value, with one direction. It does not have multiple values depending on the imputed presence or absence of various nearby objects. That would be like having two thermometers, one that tells you the temperature of the room with the air conditioning on and another with the air conditioning off. Instead, a thermometer measures the actual temperature in the actual room, and not the imagined temperature in some speculative room. A compass does the same thing - it measures the real magnetic field, and not some imaginary field for some counterfactual arrangement of nearby objects.

I am not claiming a compass can measure a magnetic field. A claim a cheap toy compass does not have a good strong pointer needle magnet like a much better quality more expensive compass. Directions that come with a compass says, keep it away from metal objects to get an accurate reading. Sometimes wind moves my TV antenna then I have to reset it. I have noticed the toy compass works best to aim the TV antenna in the correct direction because the toy compass is not attracted to the metal antenna tower from 5 ft away. I have to walk 20 ft away from the antenna using the good quality compass. The good quality compass is effected by all the metal objected in the yard, patio furniture, cars in the driveway, garden tools leaning up against the tree, tiller in the garden, lawn mower in the shed, chain link fence around the yard. I have noticed the good quality compass can be used to find nails in the sheet rock wall once I find a nail I know there are other studs in the wall all 16" apart this helps me hang pictures on the wall for my wife. The toy compass is a pain in the butt trying to find nails in the wall but when either of the compass get close to a nail the needle points right at the metal nail.

Do this experiment. Buy a stack of magnets here. https://www.ebay.com/itm/Super-Strong-N35-Round-Disc-Neodymium-Mini-Fridge-Magnets-Rare-Earth-New/173384504513?var=&hash=item285e8594c1 put the stack on a float in a plastic tray of water in the yard away form all metal. The float boat will rotate to North south direction. Now move a piece of metal near the plastic tray the float boat will move toward the metal. Compass needle does the same thing.

 

[sophiecentaur]

None of what you wrote is correct.

I'm not sure what you referred to here because you didn't actually quote one of ~Gary's posts. I am not sure that he has been putting across what he really means. It could be muddled rather than plain wrong. - could be a language thing? (@gary350 ?)

But it is true to say that finding magnetic North is affected by nearby objects and their actual orientation. Ships (even humble boats. sometimes) have various arrangements round a compass binnacle which attempt to correct for the iron in the vessel. There are permanent magnetic effects, varying electromagnetic effects and there are effects of the susceptance of the ship parts on the Earth's field. See this link.
On top of that, doing it properly involves using a 'Deviation Table' which is a set of deviations from the ship's apparent magnetic N and the magnetic N on the chart. You 'swing the ship' over 360° and take readings every few degrees. and comparing with a known geographical bearing. If you want a good magnetic bearing, you correct with the deviation table and then you apply the Variation, which is on every chart. That tells you the variation on a certain date with a yearly rate figure to correct further.
Something I have not understood is how a Fluxgate compass is reckoned to be better behaved than a magnetic needle. Also, why do they tell you to mount a fluxgate sensor low down in the ship? That could be very near an iron keel.

 

[Vanadium 50]

And all of this reminds me... we just replaced some stuff in the console of the boat, and the added metal is affecting the local magnetic field differently than what had been there

Back in Days Of Old, the ship's compass was placed in something called a binnacle. It had two nearby iron correcting spheres to compensate for all the ferrous material on the boat. Add (or remove) ferrous material and "simply" readjust.

 

[Vanadium 50]

But it is true to say that finding magnetic North is affected by nearby objects and their actual orientation.

Sure. But it's not true that a cheap compass is not affected by the nearby objects and only the Earth's magnetic field. (The claim "A cheap $1 toy compass is more accurate in town because near by metal things do not effect it.") As mentioned, the magnetic field is what it is, and nearby objects can change it, but change it they do. A cheap compass does not ignore these changes.

 

[Nugatory]

Back in Days Of Old, the ship's compass was placed in something called a binnacle. It had two nearby iron correcting spheres to compensate for all the ferrous material on the boat. Add (or remove) ferrous material and "simply" readjust.

Yes, and your scare-quotes around the word "simply" are well-taken - it's trickier than it sounds.

 

[Dale]

Why are we using a compass at all. I thought that the goal was to find when local solar noon was. That can be simply looked up on the net on multiple websites which have been provided.

@gary350 can you remind us what the goal is? To my understanding a magnetic compass was not essential.

 

[gary350]

I just learned something new. Assume your standing on the sun looking at Earth with true north straight up to the north star and magnet north to the right. 6 hrs later Earth has rotated 90 degrees and magnet north is pointing straight at the sun. Another 6 hrs later magnetic north is pointing to the left. 6 hrs later magnetic north is pointing away from the sun. Depending on where you live on Earth the angle between magnet north and true north will be different at solar noon for you and your geographical location. There are 6 time zones from east Canada to Alaska if magnetic north pointing straight at the sun in Alaska at the exact same time magnet north is point to the right in Canada. But 3 months later as Earth rotates around the sun magnet noon is now rotated 90 degrees to the west. If I take a magnet noon reading with a compass and homemade type sun dial rod stuck in the ground at 45 degree angle north the angle between solar noon and magnet noon will never be the same from day to day. I probably will not notice changes from day to day but changes from month to month will be easy to detect. I was hoping to use magnetic noon to find solar noon by checking the angle of the shadow to true north but it is changing every day. 2 times every year solar noon and magnet noon will be at the same time. 3 months later and 9 months later magnet noon will be as far as it gets from solar noon.

The goal was to find solar noon buy knowing where magnet noon is. Lots of people suggested use noaa but so far I have not been able to know if the answer I get is correct. From what I just learned magnet noon changes every day so it makes no sense to use it to find solar noon.

I never thought about it until now but if you drive your car from east Canada to Alaska through 6 times zones you have driven 1/4 of the way around earth.

 

[Dale]

I never thought about it until now but if you drive your car from east Canada to Alaska through 6 times zones you have driven 1/4 of the way around earth.

If you go to the north pole and walk around it then you have walked all the way around the earth. The closer to either pole you go, the shorter distance it is.

a cheap toy compass does not have a good strong pointer needle magnet like a much better quality more expensive compass

I suspect that the difference between a cheap and a good compass is more in the bearing than in the strength of the magnet. Cheap bearings get "stuck" so the resulting compass is less accurate.

 

[anorlunda]

When boating on New York Canals, I used my magnetic autopilot. I had to stay alert because when passing under low bridges, the autopilot would lurch as much as 40 degrees. It was interesting because it only happened with ancient bridges, not modern ones. I'm not sure if the old bridges had residual fields left from when they were manufactured, or if they acquired it in their century of service. A reasonable guess is that one of the specifications for modern structural steel is that it be demagnetized before leaving the factory.

By the way, a ships binnacle is hardly an obsolete term. Nor are the metal balls used to adjust compasses obsolete. What makes compasses expensive has more to do with gimbals and damping than accuracy. As the boat rolls and pitches and yaws in rough seas, it is most annoying to have the compass heading swing also. Also interesting, is that the same difference between cheap and expensive GPS marine instruments. The cheap ones show near-instantaneous values, the expensive ones suppress periodic oscillations by active digital filtering.

As @sophiecentaur said, a marine compass, regardless of how accurate the claim, must use a deviation card which is calibration by experiment.

I'm afraid we're getting off-topic, but this stuff is interesting. The best answer to the OP was given by @Helios in #5.

 

[Mark44]

Now move a piece of metal near the plastic tray the float boat will move toward the metal.

It depends on the kind of metal. If you put a piece of aluminum or any other nonferrous metal near the magnets, they won't be attracted to that metal.
I believe that this misconception about metal is just one of the things you said in post #27 that Vanadium 50 referred to when he said that none of the things you said were correct.

 

[sophiecentaur]

The goal was to find solar noon buy knowing where magnet noon is.

Whatever is "magnet Noon"?

 

[sophiecentaur]

By the way, a ships binnacle is hardly an obsolete term.

When everything else has stopped working and they've jury rigged a piece of canvas to the radio mast, they can still tell where North is.

 

[anorlunda]

What I am trying to do is find out, when is the SUN is exactly straight up at my house.

The goal was to find solar noon buy knowing where magnet noon is.

You are contradicting yourself and confusing the posters with your conflicting goals.

To find true north, there is no need to even mention magnetic north. Use the method @Helios gave:

You draw a circle on the ground. You put a straight-up stick in the center. The shadow will cross that circle before noon and after noon. Connecting those points will give you and east-west chord and perpendicular to that a north-south chord.

Or, if your goal is to set up a sundial in the Northern Hemishphere, it is more than accurate enough to point to Polaris, The North Star.

 

[gary350]

Sure. But it's not true that a cheap compass is not affected by the nearby objects and only the Earth's magnetic field. (The claim "A cheap $1 toy compass is more accurate in town because near by metal things do not effect it.") As mentioned, the magnetic field is what it is, and nearby objects can change it, but change it they do. A cheap compass does not ignore these changes.

It was only more accurate in my yard because it was not effected by all the metal in the yard. Your right the high price compass is best if your hiking in the wilderness.

https://scontent-atl3-1.xx.fbcdn.net/v/t1.0-9/36688576_2336260109725061_6862444676205510656_n.jpg?_nc_cat=0&oh=f590686a6ee74ac7262ebb06b786eb04&oe=5BA149DE

 

[Vanadium 50]

It was only more accurate in my yard because it was not effected by all the metal in the yard.

Repeating a wrong thing does not make it right.