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    Re: Use of AH for professional navigation
    From: Magnus Sjoquist
    Date: 2011 Oct 6, 10:42 +0200
    I am talking about artificial horizons for marine sextants, shipboard use.
    In teaching students how to astronav, I have also used buckets of water as reflecting device with very godd outcomes. The bucket horizon is of course useless on a moving vessel, but adds to the understanding of what corrections to apply and how the sextant works. It also gives the student the "YESSS"-feeling and adds to his/her interest for the Art of Navigation in general and the Art of Astro Navigation in particular.
    Re-reading some of present and previous discussions on AH's I have the impression that the core subject is marine surface navigation, even if air-navigation and military uses also in a wider perspective surely is relevant for the question about what is "horizontal". Training in areas without visible horizon is one very important step towards being an Astro Navigator.
    Sorry to all of You  if I have misunderstood the topic at hand.

    ----Ursprungligt meddelande----
    Från: garylapook@pacbell.net
    Datum: 2011-10-06 09:53
    Till: <NavList@fer3.com>
    Ärende: [NavList] Re: Sv: Re: Use of AH for professional navigation

    Are you talking about the type of artificial horizons we have been discussing, a horizontal reflecting surface, or are you talking about artificial horizon sextants?


    --- On Wed, 10/5/11, sjoquist.magnus@telia.com <sjoquist.magnus@telia.com> wrote:

    From: sjoquist.magnus@telia.com <sjoquist.magnus@telia.com>
    Subject: [NavList] Sv: Re: Use of AH for professional navigation
    To: NavList@fer3.com
    Date: Wednesday, October 5, 2011, 11:46 PM

    Hi Gary  -
    Short answer is: Fine!
    Source: Own experience from the early mid -80's and early -90's (large commercial vessels =  quite stable platforms. Rolling yes, pitching yes, vibrations no!).
    Sub-source: Reports from former "students" (cadets Royal Swedish Navy) who have tried out some quite advanced instruments during their astro-training weeks onboard GLADAN and FALKEN (Navy Schooners).
    Longer answer: Assuming You "accept" a precision in position somewhat lesser (say around 5 NM uncertainty) than You would for daylight/twilight observations (say better than 2
    NM) under good conditions, You are happy to have it onboard, although it can be hard to persuade the shipowner to include it in his standard equipment on his vessels).
    Also: Takes a bit of training to get good sights, which is quite OK. Not a bad way to spend night-watches at sea.
    ----Ursprungligt meddelande----
    Från: garylapook@pacbell.net
    Datum: 2011-10-06 08:17
    Till: <NavList@fer3.com>
    Ärende: [NavList] Re: Use of AH for professional navigation

    How do these artificial horizons work on shipboard?


    --- On Wed, 10/5/11, Magnus Sjoquist <sjoquist.magnus@telia.com> wrote:

    From: Magnus Sjoquist <sjoquist.magnus@telia.com>
    Subject: [NavList] Use of AH for professional navigation
    To: NavList@fer3.com
    Date: Wednesday, October 5, 2011, 10:43 PM

    Dear All -
    AH's are not only for desert/Arctic Navigation or for backyard training.
    They are also provide means for 24hour astronav on the High Seas.

    (Combined with dark-vision telescope we are talking about costs around 10.000 USD or more which normally is out of range for private (or students) budgets)).

    Magnus Sjoquist
    (Thanking You All for very interesting reading on this and other matters).
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