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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
days.

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.

cheers,

Robert Eno
----- Original Message -----
From: Grobler, Steven 
To: 
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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