NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Peter Hakel
Date: 2010 Mar 17, 18:34 -0700
Latitude: N 41 deg 57.4' +/- 11.8'
Longitude: W 87 deg 43.1' +/- 16.0'
This result differs from your actual location by S 0.2' in latitude, and W 5.0' in longitude.
@Antoine:
The source code and input file are attached. The program calculates the crossings of all possible LOP pairs. Then it calculates the average latitude and longitude, and the associated standard deviations.
Even in this case the "error bars" still appear to be unnecessarily large. Suggestions of a more appropriate statistical procedure would be welcome.
Peter Hakel
From: Frank Reed <FrankReed@HistoricalAtlas.com>
To: NavList@fer3.com
Sent: Wed, March 17, 2010 2:32:01 PM
Subject: [NavList] Today's octant sights
Here are the Sun sights I took with an old ebony octant c.1840 this morning on the shore of Lake Michigan:
10:29:00 35-00
10:31:35 35-23
10:33:31 35-38
10:35:39 35-52
10:37:49 36-12
10:39:39 36-27
10:41:44 36-44
10:43:11 36-58
10:45:39 37-13
10:47:23 37-29
Times are CDT. The "watch" was 10 seconds slow, so add 05:00:10 to get to GMT. These are all Sun LL (35-00 means 35 deg 00'). Index correction was 0 since those old octants were supposed to be zeroed out every time. Height of eye was 16 feet above Lake Michigan, weather conditions near standard, and the actual location was 41d 57.6N, 87d 38.1W. The horizon was a little vague. By my reductions, the mean error in the sights is about 1 minute of arc and the standard deviation is about 1 minute of arc. Pretty good considering that this is a normal octant with no telescope and a discolored vernier that I really have to squint at to read.
"Rapid-fire" fix anyone?
-FER
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