NavList:

I pointed out a page in an old logbook wth a lunar calculation from the 1840s. It makes an interesting puzzle but it's hard to read, and I know some of you don't like following links. So here's a transciption of the calculation. Words in brackets are mine. Everything else is straight out of the logbook. I have added leading zeroes to many of the angles and logs so that they will format correctly (at least I think they will).

 

Here's the Puzzle:
See if you can figure out the vessel's position from the information here. Most of it makes sense, but there are a few little oddities in the calculation... First things first, you need to figure out the year. That means you'll need to find a geocentric lunar distance among the numbers below and then compare it with a modern calculation (e.g. from HistoricalAtlas.com/lunars). You'll also want to figure out what's gong on in each of the eleven sections of the calculation. For an example, section 4 is a calculation of the Moon's (augmented) semi-diameter. What method is being used to clear the lunar?

 

[BEGIN]
Distance from the Sun and Moon taken
February 9th at 5P.M. in Long 140..00W Long [sic] Bound
around Cape Horn
----------------------------------------------------
[Section 1: top middle]
Sun
24..57
00..12
---------
25..09

 

[Section 2: immediately to the right of above]
10..24
00..20
---------
10..04

 

[Section 3: at right top]
Chronometer
01..19..00
00..50..30
--------------
02..09..30

 

[Section 4: at right middle]
15..17  [labeled "8th"]
15..23  [labeled "9th"]
---------
00..06
---------
00..01
---------
15..18
00..03
---------
15..21

 

[Section 5: immediately to the right of above]
56..05  [labeled "8th"]
56..30  [labeled "9th"]
---------
00..25
---------
00..06
---------
56..11

 

[Section 6: left column]
105..57..45   [could be 51 or 52 or 57]
000..02..45
----------------
105..55..00
000..13..08   [??]
000..15..21   [carried over from right]
----------------
106..23..29
000..03..14
----------------
106..26..43
000..27..48   [from log calculation below]
----------------
105..58..55
104..56..18 
----------------
001..02..37

 

[Section 7: middle: 1st column of logs]
00.5057
10.3716
09.9818
-----------
00.8591

 

[Section 8: immediately to the right of above. 2nd column of logs]
00.5057
10.7574
10.5297
-----------
01.7928

 

[Section 9: just below 2nd column of logs]
24..54
02..54
----------
27..48

 

[Section 10: aligned with lower right of left column]
4586 [proportional logs]
3143
---------
1443

 

[Section 11: at bottom, aligned with "1443"]
02..09..07  [GMT]
12
--------------
14..09..07
14..09..30
--------------
23 [seconds]

 

[END]