# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: body not aligned with reflection in artificial horizon
From: Robert Eno
Date: 2007 Nov 25, 10:55 -0500

```You have be a bit confounded David.

I have been using artificial horizons for years and have never encountered
this problem. If you have adjusted your sextant for index, side and
perpendicularity errors, you should be in good shape. The image of the sun,
when it reaches the lowest point on its arc (if you are rocking the
sextant), should be directly above or below the reflected image.

A couple of other things come to mind:

If you are using a glass horizon, you have to ensure that it is perfectly
level. But you also indicated that this problem is occurring in a pan of
water which is self-levelling.  Try shifting your position so that the sun,
the pan of oil and you, are all in a straight line.

Again, perhaps I am misinterpreting the nature of the problem you are
describing.

Let me know how you make out.

Robert

----- Original Message -----
From: "landlocked"
To: "NavList"
Sent: Sunday, November 25, 2007 10:16 AM
Subject: [NavList 4077] Re: body not aligned with reflection in artificial
horizon

>
> Robert:
>
> Rocking the sextant only shows that the body is indeed misaligned.
> That is, the body which is typically to the left of the mirror or pan
> of oil will become aligned when rocked to the right, yes.  But rocking
> raises the object above the bottom of its rocked arc, and this assures
> that alignment is false, and therefore, that the reading is
> inaccurate.
>
> I think I just need to get better at correcting the sextant for side
> error or perpendicularity.
>
> I'll keep you posted.
>
> David C.
>
> On Nov 24, 9:28 pm, "Robert Eno"  wrote:
>> David
>>
>> Try rocking the sextant as you would for a sea horizon observation. This
>> should do the trick, unless I have misunderstood your question
>>
>> Robert
>>
>>
>>
>> ----- Original Message -----
>> From: "landlocked"
>> To: "NavList"
>> Sent: Friday, November 23, 2007 3:52 PM
>> Subject: [NavList 4064] body not aligned with reflection in artificial
>> horizon
>>
>> > Even after adjusting my sextant as well as I can for perpendicularity
>> > and side error, I still have the following problem when using an
>> > artificial horizon:  When I bring the body down to the horizon
>> > (regardless of whether it's a pan of water or a mirror), the "brought-
>> > down" body is well to the left of the body reflected in the artificial
>> > horizon.  Have I not corrected enough for perpendicularity?  What
>> > other error might this be?
>>
>> > David C.- Hide quoted text -
>>
>> - Show quoted text -
> >
>

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