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    Re: RAF MK9 Bubble Sextant
    From: Robert Eno
    Date: 2003 Jan 18, 12:18 -0500

    Happy to oblige,
    Your problem with the bubble chamber is that the fluid -- hexane -- has
    likely leaked out somewhere. I have a set of hand-drawn instructions on how
    to re-fill the chamber, given to me many years ago by probably the last
    fellow on earth that actually knows how to fix these things.
    I will dig them up and try to send them to you as a PDF over the next few
    You are correct about the function of the little control knob on the
    averager: it allows you to select either a one or two minute averaging time.
    Sounds like you have a Mk IX BM model which should have a dual eyepiece. Is
    this so?  I have one of these in my collection. Unfortunately, the fine
    adjust knob is very stiff and I have not been able to figure out how to
    loosen it.
    Robert Eno
    ----- Original Message -----
    From: Grobler, Steven 
    Sent: Saturday, January 18, 2003 4:57 AM
    Subject: RAF MK9 Bubble Sextant
    > Good day all,
    > I've recently acquired an old MK9B RAF sextant and I am hoping that
    > someone could shed some light on a few issues (I've read some of the
    > previous posts and I have a copy of the MK9A manual, courtesy of Clive
    > Sutherland's earlier posting).
    > I am not intending to use the sextant seriously, its more of a hobby
    > item at this stage.
    > 1. I am unable to produce a bubble because the bubble chamber is only
    > partially full of fluid.
    > Could anyone explain the principle of operation of the bubble device
    > itself?
    > What fluid is used?
    > Could I refill it?
    > If so what would be the procedure?
    > 2. my sextant (the B variation) has an additional control on the
    > clockwork averaging mechanisim, near the winder - a small two position
    > selector marked I and II. I guess this might change the averaging time,
    > or number of averages...
    > Could anyone confirm?
    > --
    > Steve G

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