Jimmy Cornell - World Cruising Routes World Cruising Routes by Jimmy Cornell

      

Other books by Jimmy Cornell
| Home | Mailing Lists | Bookstore | Weather | Tide Predictions | Bowditch |

Re: Anomalous dip. was: [NAV-L] Testing pocket sextant.

From: Bill (no email)
Date: Fri Jun 16 2006 - 17:20:01 EDT

  • Next message: Marcel Tschudin: "Re: Anomalous dip. was: [NAV-L] Testing pocket sextant."

    George

    > I've just posted a meassage, in the hope of reducing
    > misunderstandings, in which was the paragraph-... large snip

    Thank you George, but I did get your meaning, hot, warm, cool, cold the
    first time;-)

    While it has been discussed on a plane too high for me to comprehend in the
    past, your latter explanations were clear and understandable to this
    layperson. Especially once you did away with ambiguous (to me) use of signs.
    You also defined "lapse rate, a missing key for me.

    George et al

    Now that I have the basic concept, what happens on a larger scale? We could
    use Frank's beach shots as an example (Indiana to Chicago, approx. 22 nm).
    Assume a thermal inversion as Frank stated. What will that do to the
    horizon relative to a horizon with well-mixed air (shift it up or down) and
    what will it do to building tops around 1100-1500 feet above water level
    (raise or lower them)?

    The problem I was having using the current Bowditch Table 15 formula was
    that the distance kept falling short, meaning if the T15 constants are
    correct, the angle measured was too large. Therefore if the horizon was
    shifted up, the building tops must have been shifted up to a greater extent.

    I understand the problem as stated may be too complex for a simple answer,
    but try a if-then.

    I also strongly suspect another problem area is the Bowditch constants.

    Thanks

    Bill


  • Next message: Marcel Tschudin: "Re: Anomalous dip. was: [NAV-L] Testing pocket sextant."



    | Home | Mailing Lists | Bookstore | Weather | Tide Predictions | Bowditch | Trawlerworld |