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  • Question on Equinox, and East and West?

    Spring equinox and autumn or fall equinox. When the sun rise or sets on the spring or fall equinox, is it "TRUE" east or west? At the point of rising or setting on the horizon, (If the horizon is flat)?

    IN other words If I put in a stake in, and line up a second stake back a few hundred yards and line it up with the point of rising or setting on the horizon, will it be true east or west?

    or will that only work on the equator?
    Push sticks/blocks Save Fingers
    ~~~~~~~~~~~~~~~~~~~
    "The true measure of a man is how he treats someone who can do him absolutely no good."
    attributed to Samuel Johnson
    ~~~~~~~~~~~~~~~~~~~
    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

  • #2
    Re: Question on Equinox, and East and West?

    i just use my compass and check my sun dial

    you of all people should be the sharpest tool in the shed

    rick.
    phoebe it is

    Comment


    • #3
      Re: Question on Equinox, and East and West?

      Originally posted by BHD View Post
      Spring equinox and autumn or fall equinox. When the sun rise or sets on the spring or fall equinox, is it "TRUE" east or west? At the point of rising or setting on the horizon, (If the horizon is flat)?

      IN other words If I put in a stake in, and line up a second stake back a few hundred yards and line it up with the point of rising or setting on the horizon, will it be true east or west?

      or will that only work on the equator?
      Isn't that what equinoxes are all about (0 East)?

      Mark
      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

      I never lost a cent on the jobs I didn't get!

      Comment


      • #4
        Re: Question on Equinox, and East and West?

        http://en.wikipedia.org/wiki/Equinox
        ---------------
        Light is faster than sound. That's why some people seem really bright until you hear them speak.
        ---------------
        “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
        ---------
        "Its a table saw.... Do you know where your fingers are?"
        ---------
        sigpic http://www.helmetstohardhats.com/

        Comment


        • #5
          Re: Question on Equinox, and East and West?

          The reason I ask is this morning (OK I know I am 2 days off), but when out and watched the sun rise, and from things that are supposed to be true ease west, (via google grid over lay) one is the power line that goes through my pasture, and I have a row of trees that line up nearly perfect with the GPS grid that Google Earth over lays,

          a few nights ago I went out and lined up the buildings and only one building on the place was in line with the north star, and it appears to be properly east west grid wise, as well as it should be.

          this morning when I went out and watched the sun rise, my guess was it was about 5 to 7 degrees north of google grid east and west, ( know a day will make some difference but I would not think that much difference),

          Last spring I did the same on watching the sun rise (in this instance it was one day past the equinox) and sighted it out of the window and marked the window sill and was in line with the edge of a building across the yard, and it as far as I can tell is north of grid east as well a number of degrees,

          when I look at Google earth and the lay out of my land and see how the original surveys "messed" up as when you can sight for miles and miles and see the roads shift back and forth and field lines shift some times a few hundred feet, (they did are really remarkable job for what they had to work with and many times counting a rag on a wagon wheel, for distance, but I have some how got curious on how to find true North south or east west, using nature, and so far Using the equinox does not seem to line up with the north star using the 3,4,5 method, or I am doing some thing wrong in where I am seeing some thing,

          I know I have always been told that the equinox is said to be east or west. but is it actually?

          Was jsut wondering if the tilt of the earth or the attitude affected the way/where it appears on the horizon?

          Bob D, I did read the article you posted, and if the answer is there I must have missed it, on the East West thing, I know it is the time when it is equal day/night time.

          Thank you for your replies so far.
          Push sticks/blocks Save Fingers
          ~~~~~~~~~~~~~~~~~~~
          "The true measure of a man is how he treats someone who can do him absolutely no good."
          attributed to Samuel Johnson
          ~~~~~~~~~~~~~~~~~~~
          PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

          Comment


          • #6
            Re: Question on Equinox, and East and West?

            This stuff always gives me a headache but it seems Zero East can only be at the Equator and any shadow cast would be X-Degrees off of true East/West based on the distance from the Equator.

            I know Charlie is into Astronomy so we will have to wait to get his take on the subject.

            Mark
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #7
              Re: Question on Equinox, and East and West?

              One of the problems with using the stars and/or sun for dead-on east west measurements is that the Earths axis actually wobbles some, so the celestial bodies change position relative to any spot on earth.

              A second problem is that the earths axis also is not perpendicular to the sun direction, so again it throws things off. That is also the reason that the southern hemisphere is hotter in summer and colder in winter. When Earth is farthest from the sun, (winter) the axis tilts the north toward the sun, giving the northern hemisphere more direct sunlight and the southern more of a glancing sunlight. The opposite happens when the Earth is closest to the sun (summer), so the southern hemisphere gets the most direct rays.

              Bottom line, you can't use celestial bodies for dead-on accurate directions on earth, unless you take into account the amount of tilt on the axis in relation to them, and the wobble in the axis.

              Go
              Practicing at practical wood working

              Comment


              • #8
                Re: Question on Equinox, and East and West?

                If you were using a compass it would be looking at magnetic north, not geographic north, and you would have to the the amount of declination for your part of the woods. Where I am in NJ it is about 11.5 deg W, for you it will be much less, maybe 5 or 6 deg. It changes over time so maps from a few years ago which show x degrees of declination for the map will be out of date but still close unless you are calculating targets for cruise missiles (yeah, I know that they really use GPS).

                Try this for an explanation of how to find north w/o a compass or GPS. Remember its only approximate but your results may be more accurate when performed close to the Spring or Fall equinox, don't know for sure.

                Shadow Method #1A or B, or method #2 (on the web page below) if you want to get a little more accurate. Remember that where you are in a time zone affects your true time. Across a time zone we recognize the time as being the same, but it actually is 4 minutes for each 5° west of the reference meridian of that time zone.

                http://www.wikihow.com/Find-True-Nor...hout-a-Compass
                ---------------
                Light is faster than sound. That's why some people seem really bright until you hear them speak.
                ---------------
                “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                ---------
                "Its a table saw.... Do you know where your fingers are?"
                ---------
                sigpic http://www.helmetstohardhats.com/

                Comment


                • #9
                  Re: Question on Equinox, and East and West?

                  An interesting question and good for you for doing the experiment. The answer probably can be found in the science of sundials. Sundials are supposed to be accurate 4 times per year. That is assuming that the gnomon has been designed correctly for the given latitude and that they are oriented to true north. Another question to consider is the accuracy of the time of sunrise and sunset. At the equinox there is 12 hours of sunlight and daylight and the sun rises and sets at 6:00 o'clock. This will only happen if you have a clear view of the horizon. This is probably only possible when on a large body of water. I suspect that the reason for your inaccurate results is that you didn't get sunrise or sunset at exactly 6 o'clock. Have you ever looked at the KDE world clock? it shows a map of the world with light and dark for day and night. It was interesting to see it at the equinox when the lines were straight. Which leads to another question, what does east or west mean at the north pole? Found this in Wikipedia at http://en.wikipedia.org/wiki/Sundial...lanar_sundials . Equation of time correction The Equation of Time - above the axis the dial will appear fast, and below the dial will appear slow. Although the Sun appears to rotate nearly uniformly about the Earth, it is not perfectly uniform, due to the ellipticity of the Earth's orbit (the fact that the Earth's orbit about the Sun is not perfectly circular) and the tilt (obliquity) of the Earth's rotational axis relative to the plane of its orbit. Therefore, sundials time varies from standard clock time. On four days of the year, the correction is effectively zero, but on others, it can be as much as a quarter-hour early or late. The amount of correction is described by the equation of time. This correction is universal; it does not depend on the local latitude of the sundial.

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                  • #10
                    Re: Question on Equinox, and East and West?

                    I know after I posted this I down loaded the sun rise times for our area, and the day that the sun rise and sun set were by time 12 hours light / 12 hrs dark were few days later than the date on the calendar, and it was much closer, to what the google grid lines were, but for the few days I went out either the east or the west there was a cloud bank on the far horizon blocking the exact location of the set or rise, so I could not compare the rise or the set with a set of stakes,

                    but I think I figured out a simple way that one could I think find solar east/west, with the sun rise and set fairly easy nearly any day of the year, closer to the fall and spring equinoxes would I think be better,
                    Set a stake on the east side of the area, before son set, go to the west side and watch for the exact rise location, (only work on flat ground) , and set a stake, wait for sun down, use the west stake that was set on sun rise, as your line up and basically on a north and south line get ready to set stake 3 in line with the second stake, you should have a "V" shaped set of stakes, the difference of the two stakes (on the east side if you started with sun rise), or the middle of the two stakes on the east side should be nearly (do to the difference of the time difference of rise and set your probly off), east / west, line,
                    Push sticks/blocks Save Fingers
                    ~~~~~~~~~~~~~~~~~~~
                    "The true measure of a man is how he treats someone who can do him absolutely no good."
                    attributed to Samuel Johnson
                    ~~~~~~~~~~~~~~~~~~~
                    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

                    Comment


                    • #11
                      Re: Question on Equinox, and East and West?

                      That sounds as if it should work. It might be easier or more accurate to have a long plumb bob made of a thick rope than using a stick for the central reference. I think that i was wrong in blaming the time of day of the observation for the inaccuracies. As long as it is the equinox, the sun will be on an arc directly overhead east to west for the full day. This is of course true every day if you are on the equator. You would not even have to do the observations at sun rise and set, as long as the 2 observations are the same length of time from 12:00 o'clock. Then there is also the matter of having to get the correct, accurate 12:00. The clock time will be accurate at only one meridian of longitude in any time zone. Still wondering about the N & S poles ??????p.s. how does one get a new paragraph in this forum?????

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