### Author Topic: Determining True North  (Read 2101 times)

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#### kbellis

• Forecaster
• Posts: 357
##### Determining True North
« on: December 14, 2018, 03:04:31 PM »

Determining true where ever you are is fun and easy!

Best viewed full screen in HD 1920 x 1080 on YouTube

« Last Edit: December 14, 2018, 03:10:23 PM by kbellis »

#### WeatherHost

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##### Re: Determining True North
« Reply #1 on: December 14, 2018, 03:12:22 PM »

I don't need a video to find north.

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#### CW2274

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##### Re: Determining True North
« Reply #2 on: December 14, 2018, 03:20:08 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

#### Old Tele man

• Singing in the rain...
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##### Re: Determining True North
« Reply #3 on: December 14, 2018, 03:24:49 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.
I use the "three rocks" method, only takes nine months to accomplish (wink,wink)!

FUNCTIONALLY, this is *how* I determine(d) "true" north for my VP2:

1) SPRING EQUINOX - at exactly NOON, placed a rock on the ground at the TOP (end) of the shadow from the pole.
2) SUMMER SOLSTICE - at exactly NOON, placed a rock on the ground at the TOP (end) of the shadow from the pole.
3) AUTUMNAL EQUINOX - at exactly NOON, placed a rock on the ground at the TOP (end) of the shadow from the pole.
4) WINTER SOLSTICE - at exactly NOON, placed a rock on the ground at the TOP (end) of the shadow from the pole.

The "straight Line" formed by the four three(*) rock locations "align" exactly NORTH(were the moss grows) - SOUTH(where the sun shines).

Done four six years ago, I "check" things every three months: "Is the shadow on rock? Yep; all's OK!" (wink,wink).

(*) the two equinox rock locations coincide midway (the equinoxes) between the two solstice extremes

« Last Edit: December 14, 2018, 06:55:13 PM by Old Tele man »
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#### nincehelser

• Forecaster
• Posts: 3336
##### Re: Determining True North
« Reply #4 on: December 14, 2018, 03:29:56 PM »

#### Old Tele man

• Singing in the rain...
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##### Re: Determining True North
« Reply #5 on: December 14, 2018, 03:46:07 PM »

I believe that's the method the Boy Scouts teach (I vaguely remember)...and works with existing tree shadows, no separate stick required.
« Last Edit: December 14, 2018, 03:55:13 PM by Old Tele man »
• SYS: Davis VP2 Vue/WL-IP & Envoy8X/WL-USB;
• DBX2 & DBX1 Precision Digital Barographs
• CWOP: DW6988 - 2 miles NNE of Cortaro, AZ
• WU - KAZTUCSO202, Countryside

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##### Re: Determining True North
« Reply #6 on: December 14, 2018, 05:02:38 PM »

#### galfert

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##### Re: Determining True North
« Reply #7 on: December 14, 2018, 05:27:20 PM »

Determining true where ever you are is fun and easy!

Nice job on the video. The narrating voice is very good also.
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#### the beteljuice

• the beteljuice
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##### Re: Determining True North
« Reply #8 on: December 14, 2018, 05:39:05 PM »
If you have an old fashioned analogue watch, then you have a sundial in reverse.

https://www.wikihow.com/Use-an-Analog-Watch-as-a-Compass
Imagine what you will KNOW tomorrow !

#### nincehelser

• Forecaster
• Posts: 3336
##### Re: Determining True North
« Reply #9 on: December 14, 2018, 06:45:58 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

It works, but I doubt for all.  Light pollution is really taking its toll on Polaris, and many people assume its a very bright star.

#### CW2274

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• Posts: 5149
##### Re: Determining True North
« Reply #10 on: December 14, 2018, 07:24:29 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

It works, but I doubt for all.  Light pollution is really taking its toll on Polaris, and many people assume its a very bright star.
Very good point which I hadn't considered being that I live where I do. The dry air, altitude, and very strict lighting ordinances here (just for this reason) make Tucson one of the very best star gazing places in the country. Polaris is very easy to spot here, and I'm certainly within the city "glow".

#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #11 on: December 15, 2018, 01:24:12 PM »
I don't need a video to find north.

Of course you don't.

#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #12 on: December 15, 2018, 01:28:54 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

Yes, that is an excellent method, though some folks may find it difficult to find Polaris, or be uncertain they're looking at the correct star. Transferring the observed azimuth between the observer and Polaris onto the ground may also present some questions for the newcomer.

#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #13 on: December 15, 2018, 01:33:45 PM »

This is an interesting approach which might appear elegant in its simplicity, at least it did to me initially; however, after further study, the observer's location and season will produce widely varying values for east-west.

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#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #14 on: December 15, 2018, 01:53:31 PM »
Most of the non-surveying methods for determining true (geographic) north that involve the sun and time, fail to properly address culmination for the observer's longitude and the equation of time. Casio's website saves having to do the math for both elements in one sleek calculator, something which might otherwise discourage folks from accurately determining true north.

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The manufacture's instruction for using a compass was what inspired this video, as the range of magnetic declination for the extremes of the CONUS not so long ago was nearly 40°. And then there's the matter of local attraction, something which is also frequently ignored and which can be just as significant in producing errant observations. My good old friend Harry, God rest his soul, always chafed over the use of the compass needle for surveys, opting instead to perform solar observations with his theodolite, WWV (with DUT corrections) and the HMSO star almanac.

#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #15 on: December 15, 2018, 01:57:01 PM »
Nice job on the video. The narrating voice is very good also.

A kind word is always appreciated. Thank you Glenn.

Kelly

#### DaleReid

• Forecaster
• Posts: 1543
##### Re: Determining True North
« Reply #16 on: December 15, 2018, 02:30:16 PM »
All very interesting.

but the question remains, how accurate do you need to be?

I don't think we're aligning the next 50 meter deep space network telescope here.  I think compass and charts for variation are all one might need.

What about the compass applications available for smart phones, especially if one wanders around enough to let the magnatometer/gps/triangulation do its thing.

And finally, so what if the data show 3 or so degrees from what 'really' is?  I might comment differently if my PhD thesis depended upon it, but for the pie charts showing average direction I'm not sure that is is critical for the future of the country and the human species to have the wind vane oriented perfectly (slight tongue in cheek).
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#### nincehelser

• Forecaster
• Posts: 3336
##### Re: Determining True North
« Reply #17 on: December 15, 2018, 02:34:12 PM »
I'd be satisfied if everyone understood the difference between True North and Magnetic North.

#### CW2274

• Forecaster
• Posts: 5149
##### Re: Determining True North
« Reply #18 on: December 15, 2018, 02:47:57 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

Yes, that is an excellent method, though some folks may find it difficult to find Polaris, or be uncertain they're looking at the correct star. Transferring the observed azimuth between the observer and Polaris onto the ground may also present some questions for the newcomer.
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

#### nincehelser

• Forecaster
• Posts: 3336
##### Re: Determining True North
« Reply #19 on: December 15, 2018, 02:51:31 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

Yes, that is an excellent method, though some folks may find it difficult to find Polaris, or be uncertain they're looking at the correct star. Transferring the observed azimuth between the observer and Polaris onto the ground may also present some questions for the newcomer.
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

I once had a person ask me how to find a full moon.

#### CW2274

• Forecaster
• Posts: 5149
##### Re: Determining True North
« Reply #20 on: December 15, 2018, 02:53:14 PM »
I do like they have for a millennia or so, use the North Star. Seems to work.

Yes, that is an excellent method, though some folks may find it difficult to find Polaris, or be uncertain they're looking at the correct star. Transferring the observed azimuth between the observer and Polaris onto the ground may also present some questions for the newcomer.
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

I once had a person ask me how to find a full moon.
Did ya pull down your pants??

#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #21 on: December 15, 2018, 03:07:13 PM »
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

LOL. Like has already been mentioned, it's not always easy to spot; unaltered image, only reduced for this forum post:

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#### kbellis

• Forecaster
• Posts: 357
##### Re: Determining True North
« Reply #22 on: December 15, 2018, 03:13:15 PM »
but the question remains, how accurate do you need to be?

That's a good question. Is half of a point on a 16-wind compass rose too much? i.e., 11.25°

#### CW2274

• Forecaster
• Posts: 5149
##### Re: Determining True North
« Reply #23 on: December 15, 2018, 03:24:24 PM »
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

LOL. Like has already been mentioned, it's not always easy to spot; unaltered image, only reduced for this forum post:

[ You are not allowed to view attachments ]
Oh good grief, it ain't rocket surgery. If you can find the Big Dipper, you can probably find the North Star. I learned how to find it when I was in single digits.

LOL. Like has already been mentioned, it's not always easy to spot; unaltered image, only reduced for this forum post:

[ You are not allowed to view attachments ]
Seriously? The only thing I see in that pic is a street light....

#### DaleReid

• Forecaster
• Posts: 1543
##### Re: Determining True North
« Reply #24 on: December 15, 2018, 03:59:31 PM »
I submit, if I can get them to load, two videos I just took of my three RMYoungs, one each Texas Wx Instruments and Peet Bro wind sensors.  The Davis is too far out of the field of view to see all the time.

And I apologize for this less than Cecil B. DeMill footage, I was zoomed all the way in with my old phone camera, and the dogs were insisting that rather than watch some blue sky, that I should throw their frisbees for them, and the end result was a pretty unsteady shot.

Nonetheless, the important thing is to see how much these sensors vary from moment to moment, and that the prop type Youngs don't even agree, although admittedly they are a few feet apart in vertical placement on the tower.  But the Peet and the TWI are very close and they sway back and forth more than one might think.

All worth watching when the temperatures are mild and a few moments to contemplate how the very local conditions vary.

It's not like landing in a 30 degree gusty crosswind, but it gives some idea how the variations pretty much negate the few degrees off one might be with setting up the sensor when mounting it.  I admit, I have used the north star, the compass (corrected), the gps and tried the sun method when I was looking for a north-point removed from the tower so I could just sight it towards the point and be happy it was within 5 degrees or so.  They all ended up pointing at a spot that a big rock just to the west of a nice birch tree, and I think that it was within a few feet of one another, and about 100' away from the tower as a reference point.

I guess a .mp4 file cannot be uploaded, or at least I can figure out.  Anyone know how to do that?
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