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  1. M

    Celestial navigation tables

    Yeah, I get it. There's really no need for my tables. I humbly thank you for an interesting discussion!
  2. M

    Celestial navigation tables

    There's a certain intellectual appeal to the topic and the stars are beautiful.
  3. M

    Celestial navigation tables

    I wonder how lone sailors (like athletes) found their position before the GPS. Sure they couldn't do DR 24h. So maybe they used some initial trigonometry to get the DR coordinates for the charts?
  4. M

    Celestial navigation tables

    I think you might use tables, forms & sextant when the power is out. Or when the GPS signal is distorted... maybe distorted GPS + functioning phone is the niche for your student.
  5. M

    Celestial navigation tables

    Any educated Finn should be able to read Swedish, but in practice, some people seem to woefully ignore the plentiful school tuition... I read Swedish, however.
  6. M

    Celestial navigation tables

    Ok, thanks. Starts to make sense now.
  7. M

    Celestial navigation tables

    Interesting comments, all. I admit I have kind of re-invented navigation. Didn't bother to read in the first place... My guess is that those systems that you have shown appear so simple because they are based on correcting an initial guess. Take for example the form @trisail has posted. I get...
  8. M

    Celestial navigation tables

    Oh, what a shame! The world is digitalising so fast.
  9. M

    Celestial navigation tables

    And what the heck is the hour angle of Aries? edit: Ok, I have a guess on this one. It might be the local hour angle of the First Point of Aries; but to know the LHA, you need an initial guess of your longitude. By the way, how easy/difficult it is to guess the latitude on the Southern...
  10. M

    Celestial navigation tables

    So, basically, you first guess the latitude and longitude, and that gives you altitudes of the stars. Then, you take observations and compare these to predicted altitudes and the difference helps you to correct the longitude? Please, bear with me and try to explain this in as simple English as...
  11. M

    Celestial navigation tables

    I wonder how the navigation forms can eliminate the need to do long divisions. All formulae for the star altitude involve a rational function of some trigonometric function of the longitude / right ascension / hour angle. This may be irrelevant for you, if you're not into maths, but consider for...
  12. M

    Celestial navigation tables

    I appreciate your comment. I don't have experience of taking sights myself. The idea was that I could use my computer program to generate the tables and then people could print those. I have the image that conventional celestial navigation requires either electronic devices or complicated...
  13. M

    Celestial navigation tables

    The answer is really very simple. You get the geographical longitude ("easting") as right ascension of the zenith minus time passed since noon, spring equinox. The time is here measured in a circular manner so that each hour contributes 360/24 degrees and each day contributes 360/356 degrees...
  14. M

    Celestial navigation tables

    Well, yes. It's actually the hour angle of the observer. You have to subtract the effect of the time to get the geographical longitude. I will check out the correct formula tomorrow.
  15. M

    Celestial navigation

    I advertised my skills to calculate longitudes in Sailing Anarchy: My question: Have you ever actually needed to use something else than GPS?
  16. M

    Celestial navigation tables

    I have developed a computer program to calculate the line of position (LOP) as a function of the latitude of the observer, and the altitude and parameters of the star. The output is the Greenwhich hour angle of the observer. Is anybody interested in this kind of stuff or is this useful? I can...


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