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    Re: Mercury artificial horizons
    From: Gary LaPook
    Date: 2013 Dec 30, 22:14 -0800
    You can see photos of my mercury artificial horizon here:


    The bowl is 3 1/4 inches in diameter at the rim and 2 1/2 inches at the bottom. I have 8.1 ounces of mercury in it and I wish I had more so that I could make one with a larger diameter since the size pool I can make with just what I have results in a small field of view requiring careful placement of my head and sextant to see the celestial objects. Just as in flight navigation, it helps a lot to precompute the altitude and set that on the sextant (double the Hc) which makes it easier to bring the desired object into the limited field of view.


    From: Gary LaPook <garylapook@pacbell.net>
    To: garylapook@pacbell.net
    Sent: Monday, December 30, 2013 9:52 PM
    Subject: [NavList] Re: Mercury artificial horizons




    From: Alexandre Eremenko <eremenko---.edu>
    To: garylapook---.net
    Sent: Monday, December 30, 2013 5:54 PM
    Subject: [NavList] Re: Mercury artificial horizons

    I have not used the mercury horizon,
    but few years ago I purchased 1 pound of mercury
    from ScineceLab.com Chemicals and Lab equipment.
    The cost was about $100 plus about $50 (don't remember correct numbers)
    for safe shipping.
    I purchased it to refill a mercury barometer (which I also did not)
    > Should I use a wooden tray or metal?
    Mercury horizons are always made of iron.
    Other metals are not safe because they amalgamate with mercury.
    I doubt that a wooden tray will be safe.
    > Should the storage bottle be metal?
    They ship it in plastic bottles. The storage made specially for artificial
    horizons is made of iron.
    > Are special permits from the EPA needed to buy or use mercury?
    No permit was required when I bought it. But the sale of mercury
    barometers and termometers was already prohibited at that time.
    I managed to buy a termometer but missed the last barometer:-(
    > I understand toxicity is low if you do not touch it or use it in an
    > enclosed area.  Is this true?
    Toxicity is low, but the problem is that it accumulates in the organism and
    may have adverse long term effects. All care should be taken not to spill
    it. Cleaning is difficult and expensive.
    It is also advisable not to inhale vapors.
    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126053

    View and reply to this message: http://fer3.com/arc/m2.aspx?i=126054

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