Need Help in Finding Accurate True North

GPS

i think it's the only trie answere here
i would start from _here

Nice find. G.A.

But where I am the sun is about straight on top of my head for several hours. Guess I need to install a long vertical bar and monitor on which side the shade falls? For what city is the example?

Hold this with the red tip pointing north....


http://www.wikihow.com/Find-True-North-Without-a-Compass

If you don't know the difference between magnetic north and true north you shouldn't be allowed to have a compass.

All you have to do is learn what the magnetic variation is at your location and add that or subtract as required will give you true north.

Finding true north is not difficult.

Years ago, when I was on the Redwoods National Park Boundary Project, the surveying crews were able to overcome the fact that they had to determine ''true north'' while working under the high cover of a redwood tree canopy, and not always being able to see the sun, let alone see the North Star (Polaris), in broad daylight, by setting up a special instrument with a little pendulum in it, from which the direction of current magnetic north could be accurately determined, after multiple readings were taken. The declination to true north was then found by referring to the current year's Euphemeris, and deflecting that angular amount, from which subsequent angles were then measured, based on true local north.

But that was decades ago, so technology must surely be providing a better, more accurate method on a greatly improved surveying instrument to today's cadastral surveyors. So, why not ask an actual Surveyor?...

They're never around when you need one.

Who are you talking to...?

The world is so disordered and confused that only the Russians now.

Your bad spelling causes your sentence to make no sense!

I "KNOW" what I am talking about!!!

Russians 'now'........now know or know now?

No magnetic compass can give you True North. You need your GPS location (Lat/Lon) or address and use a site Like This to calculate your magnetic deviation.

Note, the magnetic deviation changes over time, so you also need the date.

The iPhone and iPad with the latest I OS software will also do this automatically for you. I have not tried it, but a simple search on the web will tell you how.

Those 2 are pretty close. The reference I posted is 2008 (forgot to include) and your's shows 0.99 deg W, moving 0.03 deg E per year, so they are pretty close.

Do it at night with Polaris; that should be close enough.

Once the system is tracking the sun you need to find it's maximum elevation. This will occur at local noon and at that instant it will be pointing true N or true S depending on your latitude. If you are within the tropics it may be slightly more complicated but I am presuming you are not.

Use magnetic North. You would not need more precision in your application than that gives you. Everyhting else is just ONE azimuth adjustment to get into the sun again!

If your device is not tracking the sun yet, you can use a sextant and a dish of water to find the sun's maximum elevation. As I said before, when the sun is at it's maximum elevation it is either true north or true south of you.

Or ask a surveyor.

How is that working. Some elaboration of this method please?

Its like in old times with the Sailors! You drink the water and set the Sextant on the Iphone and voila you come up with true North!

_{^{PS did you get the hint with the drinking?}}

I thought the water was to put the iPhone in. Where is that name coming from?

Sex..Tant?

That is from the anomaly of the water because you put the IPhone in.

My guess here is it is from the position you are in while measuring the Tant!

Using a magnetic compass on or around steel structures is pretty futile. So even if you have the mag deviation you're never sure what you are deviating from...

I'm not sure what type of compass is in your smart phone. If it derives its directionality with the GPS turned on whilst moving then your proposed method of two bearings and drawing a line to average them will be pretty good.

The compasses on non smart phone GPS calibrate themselves in motion and are pretty good to use as a pointer too.

The way I align paraphernalia which needs to point at precise bearings is to site a distance object (landmark, geo feature etc) at that bearing and then point the axis at that target.

If your compass can't give you a trustworthy siting then use a map to determine what might be exactly at true north.

Use your smart phone to go to Googleearth and see what target is north of you or if there are any features (roads are good) that you could use as a reference bearing.

Using an analog watch, set the watch to the true time at the current location making due allowance for the longitude, which may not be a multiple of 15 degrees, and any daylight-saving time that may be in force. Point the hour hand in the same direction as the sun with the watch horizontal. In the northern hemisphere, halfway between the hour hand and 12 noon is south. In the southern hemisphere, halfway between the hour hand and 12 noon is north. It's that simple.

Get a compass. That is magnetic north. Find out what the magnetic variation is in your region and add or subtract the magnetic variation. The magnetic variation will have +/- variation depending on your latitude and longitude. You can probably find that information online.

My smart phone compass app gives me the heading in degrees and the magnetic declination.

declination?

Difference between true and magnetic north.

Variation.

OK, the angular variation between true and magnetic north.

Magnetic declination calculator

This site ↓does it for you.

Magnetic Declination

My apologies. In marine navigation declination has a completely different meaning

http://en.wikipedia.org/wiki/Declination

and we use the term variation for the compass error due to the magnetic pole not being at the true pole. And the other common compass error is deviation which is due to local magnetic influences as someone else warned about.

No need to apologize.

Those here who know me will point out that I am wrong as often as I am right. Or, more so, depending on the topic.

I think the difference is we are dealing with a fixed position in this case, and not having to deal with a constantly moving view of the sky.

Where's the OP gone to?

How about letting us know if you've worked out a solution or not.

While my experience does not involve quite as large a dish as yours, (I used to install C -band satellite dishes) the basics are still the basics:

(1) the mount has to be level within 1/4 degree (or the post be plumb to the same criterion).

(2) Use a compass to site through your mount (can use holes in a couple of plates if so equipped) to a point to the south (compensate for magnetic reading in local area to true south. Repeat this observation to a point north of your mount. Use a chalk line to mark the N-S line if you wish, or use a tie string. If you have one of the more modern GPS units, you can mark locations down to within arcseconds of longitude. If you have two points with the exact same longitude reading, a line through them is true north/south.

(3) At least at this point your should be within 1 degree. If you are not within your specification of 1/2 degree, then there will an arc error in tracking the sun, and no azimuth adjustment will really take care of this.

To zero in on the exact true rotational north, compare your line with Polaris at some point in time after midnight, while vigorously slinging a dead cat around your head for luck. OR you could use the sextant method on a true level surface (float) to read solar zenith for a number of days in a row. OR OR you could simply mount your dish, use a target on it that is larger than your planned target by a factor of four or so, and let it burn the solar marks on the big target as you track through a day. You can make adjustments based on the burn line, until you get the smallest burn line you can achieve. Hope this helps.

Does a West Texas sail cat work for this?

Is a sail cat sort of like a skip rabbit? They usually have an exceptionally low profile as found lying on the ground. While slinging the cat, beware the horns of Anubis, the jackal.

May the eye of Horus guide you in your quest.

May Set not intervene with chaos.

Bast the cat, if you know her inscriptions from the scroll of life, will also bring you good luck.

Above all is the object of your aim, Ra will ultimately be the true guide for the quest.

If you have a topo map the declination of magnetic north will be given. Using a compass with a bezel ring (azimuth) you can adjust your compass to align with true north. See bezel ring on compass.

There can be some minor changes in magnetic north and I believe there are numerous sites you can use for correction. However, these are usually minor, otherwise they would not hard print the reading on the topo.

Here is some info from backpacker you may find useful:

COMPASS TIP: Declination 101
Maps are oriented toward geographic, or "true," north (the North Pole), but compass needles point to magnetic north, a place that wanders slowly within the Canadian Arctic. The difference in angle is called magnetic declination, and it varies from 21 degrees west in Maine to 26 degrees east in Alaska. That's why you should buy a compass with adjustable declination and set it properly.

On most compasses, adjusting declination is done by turning a tiny metal screw on the rotating compass needle housing. Look for declination on the lower left portion of your topo map; you'll see two diverging lines with the angle listed between them. If it says "16 degrees east," rotate the compass housing so the magnetic north/compass needle mark sits 16 degrees to the right (east) of the true north orienting lines. Twist the screw to reach the proper orientation.

Nadam!!

What's happening dude?

Have you sorted out your tracking yet?

I am amazed that this blog is still active when it should have been finished ages ago.

1) A solar tracking system does not need to "know" where true north is. It only needs to know where the sun is each day all the time.

2) It does not even need to be accurate t0 even the nearest degree. If its correctly designed, even to the nearest couple of degrees!! If even 1% of the maximum possible energy is missed due to a cheaper less accurate system, the costs saved exceed the loss.....

What many forget is that a Sun tracking system only needs to know the exact time of day (and night!) to know EXACTLY where the sun isat any point in its travel around the world.

Furthermore, the "altitude" of the Sun at any give time on any given day of the year is also fixed. In fact it repeats itself twice a year, but I do believe that even if the sun's midday elevation is only set as a "mean" say once a week, it would be close enough and the adjustment could be easily and cheaply made using some form of microcomputer.....and if more accuracy is desired, then set the mean more often, adjusting from sunrise to sunset of course.

But if the unit is set up so that it reflects the arc of the sun, (is that a Polar setup? I have forgotten!), then a simple hand adjustment once a week (or less!) for altitude would be sufficient for probably 99% of the power of a complex and properly working system!

Once a system has been tweaked to get the best output (function of day, date and time), it, keeping a table of where it should be at any time and date.....

Sun following systems almost always have problems with nights, clouds and dirt. Its best to have nothing to do with them for those reasons alone!!!

If other options are not viable for some reason, you can always try going ''old school''.

First, consult an appropriate calendar, or similar source, and find out which is the ''longest day of the year''.

On that day, go to the site, and improvise a large ''sundial''.

Then, mark on the ground the path of the end of shadow of the sundial from, say, 11:30 AM to 12:30 PM.

Then draw a ''ray" on the ground from the center of the base of the sundial to the closest point on the resulting wide, shallow parabola on the ground.

If done carefully enough, that ''ray'' will ''point'' to true local north, within a quarter of a degree, east or west...

Nicely put!!

By the way, a radius that is thirty-five units long, and is swung two units left and right, will subtend an arc of one-half-of-one-degree...

QED...

everything is cool but the continents are on a move - as a result of global warming or similar climate trends the random glaciers are melting - and there are severe systematic and other orbital variations - to spare from all this science get your "reference frame" data corelate it with UT0 + <unknown by ci139>

if it's not solar telescope but a powerplant unit the above mentioned methods may appare consistent enough

OP has gone very quiet on us.

Nadam, have you sorted out your sun tracking?