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go back to the "A-10 Sextant Maintenance Manual" thread December 6,
2007 for more info on maintaining the A-10,

gl

On Nov 28, 11:15�am, engineer  wrote:
> Bruce
>
> There shouldn't be any backlash with an A10, as it is provided with a
> backlash spring. The index bearing after 60-odd years is often in need
> of lubrication to ensure free movement (I once had one completely
> seized). The bearing can be difficult to pull apart and reassembling
> with the anti-backlash spring correctly tensioned can be a trying
> exercise. You can probably improve the index error by setting the
> instrument to a sea horizon, removing the read-out counter, setting it
> to zero (allowing for dip) and replacing.
>
> I will be covering these and other details in an e-book on A10
> restoration, due out at the end of February. It will be along the
> lines of my e-books on the reconditioning of the Mark IX series bubble
> sextant and my "Naked Nautical Sextant". Seewww.sextantbook.comfor
> details. Meanwhile, you can contact me off line about your A10 if you
> wish.
>
> Bill Morris
>
> On Nov 28, 4:08�pm, bruce hamilton  wrote:
>
> > All times GMT 27 Nov 2008
>
> > A-10 Sextant with 31.5' index error off the arc (horizon reading is lees
> > than zero in case if am mixed up)
> > Sextant has no other calibration. I frequently get LOP's within 2 miles
> > of my AP so I am happy. It has backlash so I try not to change
> > directions. �I suspect some other error as stars with higher altitudes
> > tend to give me bigger errors.
> > I am actually quite surprised that I am getting a fix that is close
> > enough to find the airport (or Bermuda) if I had do. I have an A-12 and
> > Mark IX, but I only drag out one an evening.
>
> > Thanks
>
> > I am presently using CelestNav 3.0 for the palm pilot to work out the
> > sites. I would appreciate any comments on the program. I like it for
> > everything but the fix calculation, but I think 3.0 is only a Beta.
>
> > AP 49d �16.1 N �123d 7.1 W
>
> > Pollux � 06:19:33 � 27d �59.3'
> > Vega � �06:16:31 � 13d � �0.3'
> > Betelg � 06:10:53 � 28d �44.3'
> > Altair � �03:56:11 � 22d �37.0'
> > Vega � �03:54:45 � 32d �06.9
> > Capella 03:52:46 � 39d �35.7'
>
>
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