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Navigation: do you know where sun rises?


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Viewing 13 posts - 1 through 13 (of 13 total)
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  • #3405407
    Ralph Burgess
    BPL Member

    @ralphbge

    The Geraldine Largay story has sparked a lot of interest in navigation, and I thought I’d share a useful online tool.   Many people don’t realize that at the temperate latitudes where most of us are hiking, the sun sun deviates very significantly from an east-west path across the sky.  There’s a superbly designed tool here to check the sun’s position during the day for any location and date.   It’s intuitive to get started by putting a location in the search box, and there are detailed instructions are at the foot of the page.

    http://www.sunearthtools.com/dp/tools/pos_sun.php

    For example, at the Grand Canyon today 29th May, the bearing of the sun during the day is shown in the image and table below.

    At sunrise, the bearing is 062, almost 30 degrees north of due east.
    The sun does not reach a bearing of due east until almost 10am.
    The sun is dues west at around 5:45pm, three hours before sunset.
    By sunset, the sun has moved almost 30 degrees north again to bearing 298.

    Make it part of your pre-hike preparation, perhaps along with checking the weather forecast, to look up this information for your hike.

     

    #3405412
    Ralph Burgess
    BPL Member

    @ralphbge

    ETA:  For Roger – locate the antipodes, add 6 months and turn your screen upside down!   No, it does the whole world, I’ve just realized that it’s fun to play around with the extreme latitudes to see what happens, and try to map that back to a 3-d visualization of the tilted orbit axis of rotation of Earth.

    And I do realize that I got Geralidine Largay’s surname wrong, but we can’t edit OPs at all now, so no way to fix it.

    – – – – –

    EDIT: name fixed – Roger

    #3405430
    Art …
    BPL Member

    @asandh

    very good info Ralph.

     

    #3405614
    Bob Moulder
    BPL Member

    @bobmny10562

    Locale: Westchester County, NY

    Make it part of your pre-hike preparation, perhaps along with checking the weather forecast, to look up this information for your hike.

    Now this is just plain fun as well as useful. Definitely matches the bearing for sunset from our deck. I couldn’t help but plug in winter solstice to compare…

    Superb idea to check this, along with moonrise/set time and phase. Sometimes a full moon is so bright it makes it hard to sleep, although no doubt it’s welcome for guys who hike all night. :^)

    I also like to use an online calculator to check current magnetic declination, which can be off by a few degrees on old maps.

    #3405617
    Ito Jakuchu
    BPL Member

    @jakuchu

    Locale: Japan

    Nice! Not only because it is a very interesting tool, but also because around my location, the sunrise bearing is 62.51˚, or less than half a degree removed from your Grand Canyon example.

    edit – checking around the globe, the variances can be great – but they can also be quite close (Amsterdam,  Mount Everest also fall roughly within half a degree from my location).

    #3405645
    Ralph Burgess
    BPL Member

    @ralphbge

    Bob, the map is prettier, but I really like the circular graph that I posted in my OP.  It includes the solstices and equinoxes as fainter black lines, so that you can see the variation during the year.

    Ito, locations at the same latitude will all look the same (for a given time of year).

    For all latitudes, at the spring and fall equinoxes the sun rises due east and sets due west.   In summer, the sun rises and sets in the north before crossing diagonally into the southern part of the sky during the middle of the day;  in winter, the sun is in the southern part of the sky all day.  (N/S reversed in Australia, of course.)

    #3405655
    Bob Moulder
    BPL Member

    @bobmny10562

    Locale: Westchester County, NY

    I love this one, Quito, Ecuador

    Now what is the tilt of Earth’s axis relative to orbit?

    #3405717
    Ralph Burgess
    BPL Member

    @ralphbge

    https://en.wikipedia.org/wiki/Axial_tilt

    Earth’s obliquity oscillates between 22.1 and 24.5 degrees on a 41,000-year cycle. It is currently 23.4 degrees and decreasing.

    ETA: I think I’ll wait until it hits 22.1 to thru-hike the PCT, maybe the weather will be more predictable then.

    #3405735
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    I just got back from a bear hunt with a visiting BPLer and at 60N in late May, if you don’t go to sleep during the “day”, the morning sun is going to hit your tent, heat it up, and wake you up sooner than you wanted.

    Strategic camp placement helps – if there’s a mountain or heavy forest cover to the NE (or NNE nearer the Arctic Circle), you can delay that unpleasantly early local sunrise.

    #3405796
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Approaching mid-winter here. The sun rises a bit to the right of North. That works.

    Cheers

     

    #3405822
    Bob Moulder
    BPL Member

    @bobmny10562

    Locale: Westchester County, NY

    It is currently 23.4 degrees and decreasing.

    I’d say that’s about right. :^)

    Quito solstice sunset bearing

    #3405924
    Rex Sanders
    BPL Member

    @rex

    I’ve learned a lot about sunrises, sunsets, and sun paths using the $10 iPhone app “Sun Seeker”:

    https://itunes.apple.com/us/app/sun-seeker-3d-augmented-reality/id330247123

    The 3D View (augmented reality) is way cool – finding sunset and sunrise locations and times from campsites is easy and fun. Does not require cell coverage for most functions. A friend and professional videographer uses Sun Seeker constantly to plan shoots.

    You can find similar apps at other prices for both iPhone and Android.

    — Rex

    #3412087
    Diane “Piper” Soini
    BPL Member

    @sbhikes

    Locale: Santa Barbara

    Weirdest thing ever. I camped up on Hat Creek Rim the other night, just a few nights after summer solstice. The light after sunset in the sky lingered a long time over by Mt. Shasta. In the morning the light appeared in the same place over by Mt. Shasta! It was so strange! I thought, surely the sun doesn’t rise in the same place it sets here, right? Then suddenly the sun pops up in another spot on the horizon, but the sky didn’t really lighten in that spot. The sun simply appeared. It wasn’t quite 180 degrees from where it set. More like 90 degrees. Very confusing.

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