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    Re: Bubble sextant trials
    From: Gary LaPook
    Date: 2007 Feb 17, 02:44 -0800

    Bowditch up though at least the 1977 edition had table number 29 with
    instructions for its use for "ex-meridian sights." This table gives
    you the corection to add to Ho so as to calculate what the meridian
    altitude would have been based on a sight of the sun taken near noon.
    Gary LaPook
    On Feb 15, 7:33 pm, Bill  wrote:
    > Alex
    > As my texts deal with marine navigation, I had surmised the fly boys with
    > bubble sextants had come up with interesting ways to use the stars.
    > > You are welcome to borrow my copy of Lecky.
    > > He is a big fan of stars (and opponent of the Lunars)
    > > and he advocates meridional altitudes of stars.
    > > Not only upper culminations but
    > > also lower culminations.
    > > (Of circumpolar stars)
    > > But he also writes that "soon the LOP navigation
    > > will be the only method used in practice",
    > > and was is right.
    > Still interesting.
    > > The Russian manual of 1966 or so, has a brief discussion
    > > of "near meridian" Sun altitudes, but nothing else
    > > except LOP. The only reason why meridian and near meridian
    > > altitudes survived to 1966 was that the reduction
    > > is very simple. With the spread of calculators,
    > > this last reason disappeared.
    > I was familiar with ex-meridian sun sights with Ho adjusted to maximum via
    > Bowditch tables.  The star thing sounds like fun.
    > > In asto navigation manuals for airplanes
    > > (I read the 2 volume set by Chichester
    > > he wrote this before his circumnavigation when he
    > > was working in the MkIX factory during WWII. Purdue
    > > aerospace library has it. I can check it for you
    > > if you wish)
    > > he also spends a lot of time on stars
    > > (rather than the Sun) emphasizing that you can have
    > > an immediate fix with two stars.
    > > And the stars are always visible from an airplane
    > > at night, and you don't care about the horizon etc.
    > Thanks.  I'll wait on Chichester until I work through the other
    > volumes/papers we mentioned on our trip to Strictly Sail.
    > Bill
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