NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: AN-5851-1 Repair
From: Dave Harwood
Date: 2011 Nov 27, 00:33 +0000
Dave,
My apologies, I could have been clearer.
I only applied a dip correction when bisecting the bubble with the natural sea horizon to establish an estimated index error. I did this to simply get an idea of the index error. I actually accomplished this from my balcony which overlooks the sea aprox 1/2 mile away from an elevation of about 250 ft. The sextant read -34' from which I subtracted a dip correction of -15.3 to arrive at an estimated -19 index error.
Finding that it was significant, I carried out the series of shots using correct bubble sextant sight reduction procedures to find an average intercept of -17.3 with a standard deviation of 2.0'. This seemed to confirm my balcony index error estimate.
Dave Harwood
From: waldendand@yahoo.com
To: NavList@fer3.com
Date: Fri, 25 Nov 2011 05:12:00 -0800
Subject: [NavList] Re: AN-5851-1 Repair
what was your dip correction?
Check on applying dip when using a bubble.
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From: Dave Harwood
Date: 2011 Nov 27, 00:33 +0000
Dave,
My apologies, I could have been clearer.
I only applied a dip correction when bisecting the bubble with the natural sea horizon to establish an estimated index error. I did this to simply get an idea of the index error. I actually accomplished this from my balcony which overlooks the sea aprox 1/2 mile away from an elevation of about 250 ft. The sextant read -34' from which I subtracted a dip correction of -15.3 to arrive at an estimated -19 index error.
Finding that it was significant, I carried out the series of shots using correct bubble sextant sight reduction procedures to find an average intercept of -17.3 with a standard deviation of 2.0'. This seemed to confirm my balcony index error estimate.
Dave Harwood
From: waldendand@yahoo.com
To: NavList@fer3.com
Date: Fri, 25 Nov 2011 05:12:00 -0800
Subject: [NavList] Re: AN-5851-1 Repair
what was your dip correction?
Check on applying dip when using a bubble.
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
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