NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: A-10 Sextant Maintenance Manual
From: Robert Eno
Date: 2007 Dec 12, 19:36 -0500
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From: Robert Eno
Date: 2007 Dec 12, 19:36 -0500
G'day Jean-Phillippe,
Indeed, these are fickle beasts but I have had
excellent success with the Plath marine sextant bubble attachment. I re-filled
and re-furbished mine well over 5 years ago and have not lost a molecule
of fluid. I use hexane, rather than xylene. I believe it is much less
harsh on seals than xylene. I've refilled a half a dozen others for people in
the USA and have not yet received any complaints. Good old German
engineering.
If you like the lighting system on the A-10, I can
say for certain that you would love the lighting system on the RAE MK IXA. In
fact I consider it to be the best lighting system of any bubble
sextant; period. I mentioned this before on the list in an exchange with
another list member but it is worth repeating here: when the bubble chamber
of the MK IX A is illuminated, all you see is a light ring around the perimeter
of the field of view and a light ring around the perimeter of the bubble. It is
simply superb for viewing even dim stars because unlike other instruments, the
light does not wash out the background stars.
While the Brits are not known for their fine
cuisine (sorry George, couldn't resist) they did make excellent bubble
sextants at one time.
Robert
---- Original Message -----
From: jean-philippe planasTo: NavList@fer3.comSent: Wednesday, December 12, 2007 2:25 PMSubject: [NavList 4301] Re: A-10 Sextant Maintenance ManualHello Robert,
You are perfectly right and I totally agree with you, A10s bubble assemblies are tricky. What I described is the process to refill the bubble to get it back in working order at least on a temporary basis to get the feel of it and take a few sights (by the way I really like the lighting system for night shots). Unfortunately It does not warrant final and durable success in any way.
It is also my experience that all bubble assemblies gradually loose part or all of their xylene over time without any obvious leak or xylene characteristic smell.
I have reconditionned 4 A10 or A10As and 5 bubble units and they all lost part of their xylene in a matter of months.
Without refilling the assemblies in a low pressure container I don't think we can do any better.
If anybody has a better experience on A10s, please speak up!
JPP
Robert Eno <enoid@northwestel.net> wrote:
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