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Weather Station Hardware => Other Weather Station Hardware => Topic started by: kbellis on December 14, 2018, 03:04:31 PM
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[youtube]https://www.youtube.com/watch?v=zMwDkzl43n8[/youtube]
Determining true where ever you are is fun and easy!
Download the PDF summary (https://www.dropbox.com/s/gzpvhot01zyjhp2/Determining%20True%20North.pdf?dl=0) of this video.
Best viewed full screen in HD 1920 x 1080 on YouTube
And please feel free to enter your comments.
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And please feel free to enter your comments.
I don't need a video to find north.
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I do like they have for a millennia or so, use the North Star. Seems to work.
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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
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[youtube]https://www.youtube.com/watch?v=WUSx0BHYTJ8[/youtube]
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[youtube]https://www.youtube.com/watch?v=WUSx0BHYTJ8[/youtube]
I believe that's the method the Boy Scouts teach (I vaguely remember)...and works with existing tree shadows, no separate stick required.
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The full Boy Scout method:
http://www.scoutsociety.org/repository/orienteering/Finding-North.html
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Determining true where ever you are is fun and easy!
And please feel free to enter your comments.
Nice job on the video. The narrating voice is very good also.
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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
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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.
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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".
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I don't need a video to find north.
Of course you don't.
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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.
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[youtube]https://www.youtube.com/watch?v=WUSx0BHYTJ8[/youtube]
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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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.
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Nice job on the video. The narrating voice is very good also.
A kind word is always appreciated. Thank you Glenn.
Kelly
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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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I'd be satisfied if everyone understood the difference between True North and Magnetic North.
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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.
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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. #-o
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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. #-o
:lol: Did ya pull down your pants??
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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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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°
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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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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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Seriously? The only thing I see in that pic is a street light....
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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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Here's another wrench in the mix...I use magnetic north. ;)
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I guess a .mp4 file cannot be uploaded, or at least I can figure out. Anyone know how to do that?
Consider uploading it to YouTube or DropBox and post a link here.
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Nice job on the video. The narrating voice is very good also.
A kind word is always appreciated. Thank you Glenn.
Kelly
I'm not Glenn. I'm guessing autocotrect changed it. :?:
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I'm not Glenn. I'm guessing autocotrect changed it. :?:
So sorry, unsure now why I thought your name was Glen...
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I'm not Glenn. I'm guessing autocotrect changed it. :?:
So sorry, unsure now why I thought your name was Glen...
NP. Name is George.
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@galfert - Nice to meet you George. I'm Kelly Bellis.
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Seriously? The only thing I see in that pic is a street light....
Here's a tighter shot which has been enhanced in Photoshop from the same night:
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Can you spot Polaris now?
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Seriously? The only thing I see in that pic is a street light....
Can you spot Polaris now?
Phffft, I can't even find the Big Dipper, without that, forget it.
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Phffft, I can't even find the Big Dipper, without that, forget it.
Here's a cheat for you:
[youtube]https://youtu.be/kEWn-JExZsM[/youtube]
Best viewed full screen HD on YouTube
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If you have a handheld GPS, especially one with waypoint averaging, you can use it to get a good approximation of true north from a given reference point.
Set your GPS to use decimal degrees for coordinates, then set a stake at the base location and use waypoint averaging to determine the coordinates of this base point. Now go north as far as you want (the farther the better, but within visual distance) to set a temporary reference point. Move east and west using the GPS readings to get the longitude as close as possible to the longitude of the base reference point and set a temporary stake at this location. Now use the waypoint averaging to determine the corrected coordinates of the temporary reference point. Compare the corrected (averaged) longitude to the averaged longitude of the base point and use this calculator (http://www.csgnetwork.com/degreelenllavcalc.html) to calculate the east/west distance correction that needs to be made at your latitude to get the longitude to match the base point longitude. Move the stake east or west as necessary and it should now be due north of the base point (within the GPS margin of error of course.) My Oregon GPS shows decimal degree coordinates out to .00001, and at 42 degrees N latitude .00001 is about 2.7 feet on a east/west measurement.
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If you have a handheld GPS, especially one with waypoint averaging, you can use it to get a good approximation of true north from a given reference point.
Set your GPS to use decimal degrees for coordinates, then set a stake at the base location and use waypoint averaging to determine the coordinates of this base point. Now go north as far as you want (the farther the better, but within visual distance) to set a temporary reference point. Move east and west using the GPS readings to get the longitude as close as possible to the longitude of the base reference point and set a temporary stake at this location. Now use the waypoint averaging to determine the corrected coordinates of the temporary reference point. Compare the corrected (averaged) longitude to the averaged longitude of the base point and use this calculator (http://www.csgnetwork.com/degreelenllavcalc.html) to calculate the east/west distance correction that needs to be made at your latitude to get the longitude to match the base point longitude. Move the stake east or west as necessary and it should now be due north of the base point (within the GPS margin of error of course.) My Oregon GPS shows decimal degree coordinates out to .00001, and at 42 degrees N latitude .00001 is about 2.7 feet on a east/west measurement.
:shock: I think I'll just keep using the North Star.
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One easy way I use to find true north is Google Earth. I found my location there, and looked for a landmark that was north of it.
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One easy way I use to find true north is Google Earth. I found my location there, and looked for a landmark that was north of it.
Google Earth Pro is an excellent resource as it's free, has the Ruler tool [ You are not allowed to view attachments ] , and is much better than Google Maps for this type of analysis.
Using Google Earth Pro to find a reference mark north of the station works well when the available imagery is at a sufficient resolution, for example:
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As Google's global collection of high resolution aerial imagery grows, being limited to 2' NAIP imagery (in the U.S.) will become forgotten, but for now, that's all that may be available in certain rural regions. Below is a comparison of 2' NAIP imagery alongside of 6" ortho imagery from MEGIS.
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:shock: I think I'll just keep using the North Star.
Here's another wrench in the mix...I use magnetic north. ;)
Compass and Polaris will be in agreement as to north only along the line of zero declination; just keep the wrench and other ferrous objects away from the compass ;)
(http://www.princeton.edu/~oa/manual/images/declus.gif)
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If you have a handheld GPS, especially one with waypoint averaging, you can use it to get a good approximation of true north from a given reference point.
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You may want to use another method to evaluate how good your Oregon, or any other single frequency handheld GPS device, like your phone, fitbit, etc., such as what I've laid out in the OP video, or what SLOweather mentioned (if you've good aerial imagery). In this quick example shown above, I stood close to the previously calculated 17wx ref waypoint that was uploaded to the Oregon 550. For those unfamiliar with the display, the triangle represents the user's current position.
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Your Oregon can be configured to display a user grid which will provide northings and eastings to the nearest 1 foot, such as it can. If a more precise device was used, a side discussion about convergence angles might come up, but at the likely short distance between marks, it would still be a moot point. Regardless, you might find using a user grid more convenient than calculating the linear distance from geodetic positions.
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Also, once you've logged your waypoint (or averaged waypoint), your Oregon can project a new point along any bearing; e.g., 0° (true), and distance.
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:shock: I think I'll just keep using the North Star.
Here's another wrench in the mix...I use magnetic north. ;)
just keep the wrench and other ferrous objects away from the compass ;)
Didn't use a compass..merely aligned the vane to true north (established by Polaris which is conveniently aligned with a Saguaro cactus in the yard and the anny pole to avoid parallax) then dialed in the declination through the console.
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Waiting for first coat of "Hammered" paint to dry - very industrial look!
Merry Christmas to you all!
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How in the world???
Beautiful execution. What did you use for the letters? Metal or wood?
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Thanks Dale.
The letters and the fins are cut from some scrap 1 x 4 PVC trim. This stuff works like clear pine without grain and is easily welded with PVC solvent; ie., Weld-On 2007 (https://www.eplastics.com/Plastic/pvc-vinyl-glue/ips2007-pt?gclid=Cj0KCQiApILhBRD1ARIsAOXWTztdlx5C7iVc3tM_yHM40qyXu3hpBKi3D2xSg7i-eyG7K-24BxnPM2QaApRkEALw_wcB), (and regular PVC pipe cement), and takes paint beautifully.
Full scale drawings of the 3" high letters and 2.5" fins are attached... oops, now they're attached :oops:. The center 2.5" high hub is Schedule 40 PVC 2" pipe. The fins are drilled and tapped (#10 x 24) for the directionals' threaded rods. The center hub is drilled and tapped (#10 x 24) for the stainless 1/2" set screws that will hold the directional in place on the mast. The letters are all through drilled 13/64".
And of course, I had to Photoshop out the wire holding the assembly in my makeshift spray booth ;)
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Taken from the CWOP Guide (https://weather.gladstonefamily.net/CWOP_Guide.pdf), v1.0 20050308, D. Helms.
All very interesting...
but the question remains, how accurate do you need to be?