
NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: learning sight reduction
From: Carl Herzog
Date: 2006 May 4, 11:07 -0500
Lu Abel wrote:
>One thing I find more than a bit annoying about US charts is that while
>all coastal and larger-area charts have edge-scales for lat and long in
>degrees and minutes, many harbor charts use degrees, minutes, and
>seconds. Since my GPS wants data entered in a consistent format (which
>I have set to degrees and minutes), when I encounter such a harbor
>chart, I have to convert seconds to decimal fractions of a minute.
>
>Out from my nav table comes this old slide rule! Put the "1" over the
>"6" (preferably on the A/B scales rather than the C/D scales) and I've
>got a very effective seconds to fractional minutes converter!
>
>
>
I had to do a very large number of these conversions on U.S. Light List
coordinates a couple years ago. I made up the table shown below and
taped it to the side of my computer screen for reference. Eventually, I
discovered I'd memorized most of it, and could fill in the blanks in my
head.
Carl Herzog
Providence, RI
Sec Dec
1 0.02
2 0.03
3 0.05
4 0.07
5 0.08
6 0.10
7 0.12
8 0.13
9 0.15
10 0.17
11 0.18
12 0.20
13 0.22
14 0.23
15 0.25
16 0.27
17 0.28
18 0.30
19 0.32
20 0.33
21 0.35
22 0.37
23 0.38
24 0.40
25 0.42
26 0.43
27 0.45
28 0.47
29 0.48
30 0.50
31 0.52
32 0.53
33 0.55
34 0.57
35 0.58
36 0.60
37 0.62
38 0.63
39 0.65
40 0.67
41 0.68
42 0.70
43 0.72
44 0.73
45 0.75
46 0.77
47 0.78
48 0.80
49 0.82
50 0.83
51 0.85
52 0.87
53 0.88
54 0.90
55 0.92
56 0.93
57 0.95
58 0.97
59 0.98
60 1.00
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From: Carl Herzog
Date: 2006 May 4, 11:07 -0500
Lu Abel wrote:
>One thing I find more than a bit annoying about US charts is that while
>all coastal and larger-area charts have edge-scales for lat and long in
>degrees and minutes, many harbor charts use degrees, minutes, and
>seconds. Since my GPS wants data entered in a consistent format (which
>I have set to degrees and minutes), when I encounter such a harbor
>chart, I have to convert seconds to decimal fractions of a minute.
>
>Out from my nav table comes this old slide rule! Put the "1" over the
>"6" (preferably on the A/B scales rather than the C/D scales) and I've
>got a very effective seconds to fractional minutes converter!
>
>
>
I had to do a very large number of these conversions on U.S. Light List
coordinates a couple years ago. I made up the table shown below and
taped it to the side of my computer screen for reference. Eventually, I
discovered I'd memorized most of it, and could fill in the blanks in my
head.
Carl Herzog
Providence, RI
Sec Dec
1 0.02
2 0.03
3 0.05
4 0.07
5 0.08
6 0.10
7 0.12
8 0.13
9 0.15
10 0.17
11 0.18
12 0.20
13 0.22
14 0.23
15 0.25
16 0.27
17 0.28
18 0.30
19 0.32
20 0.33
21 0.35
22 0.37
23 0.38
24 0.40
25 0.42
26 0.43
27 0.45
28 0.47
29 0.48
30 0.50
31 0.52
32 0.53
33 0.55
34 0.57
35 0.58
36 0.60
37 0.62
38 0.63
39 0.65
40 0.67
41 0.68
42 0.70
43 0.72
44 0.73
45 0.75
46 0.77
47 0.78
48 0.80
49 0.82
50 0.83
51 0.85
52 0.87
53 0.88
54 0.90
55 0.92
56 0.93
57 0.95
58 0.97
59 0.98
60 1.00
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To unsubscribe from this group, send email to NavList-unsubscribe@fer3.com
-~----------~----~----~----~------~----~------~--~---