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    Lunars aboard a Schooner -- 1823
    From: Frank Reed CT
    Date: 2004 Aug 7, 14:45 EDT
    Here's a peek at navigational practice aboard an American commercial vessel in 1823. This journal is "Log 507" in the collection of the Blunt-White Library at Mystic Seaport. It can be accessed online as scanned pages but it has not been transcribed to text. The journal was kept by a navigator who was recognized by his captain as an expert in nautical astronomy (there is a letter of recommendation in the journal saying as much). I have quoted here everything of navigational interest in this journal paying special attention to the use of lunars. Contrary to the impression one might get from some modern descriptions on navigation in this period, dead reckoning was the trusted method of finding longitude despite its shortcomings. Lunars were used as a frequent check on the dead reckoning of longitude.

    The author is a mate aboard a medium-sized schooner with a crew of 11 on a passage to Java. The vessel's name is not directly recorded. Possibly it's the schooner Weymouth since he later notes it has "sailed" (as in 'sailed without me') when he checks into the Batavia Hospital. There are eight lunars (which I have marked #LUNAR#) attested in the four month period from New York to Java: 4-28-1823 to 8-28-1823 so the average interval is two weeks with considerable variability. In the entries below words in parentheses are my comments. Anything else is directly quoted from the journal. There are a several entries that appear to be lunars but are actually "lunars by account" --earlier observations advanced forward using dead reckoning. This is something to watch out for in old log books. I've been studying a logbook from 1809/10 which in one section lists "Long Lunar" for every single day for months on end. That looks impressive until you notice that the lunar longitudes are moving in lock-step with the "Long DR". It's a very small number of actual lunar observations being carried forward using the daily dead reckoning.

    It's the Spring of 1823. The Voyage Begins at New York...
    Apr 28, 1823
    At 3PM Sandy Hook Light bore NW by W dist 8 miles from which we take our departure.

    May 1, 1823
    (first longitude listed --it's a DR lon)
    Lat DR: 38 08N Lon: 67 35W

    May 4, 1823
    We have had nothing but head winds since our departure. Kept in the Gulph Stream and hope its influence has been considerable.
    Lat DR: 39 28N Lat Obs: 39 32N Lon: 63 11W

    May 5, 1823  #LUNAR#
    We obtained some indifferent sights at 11AM. Longitude resulting the from the mean of the distances 57 41W -5 from 11 to Noon = 57 36W. (lunar acct brought forward to noon) (elongation of Moon from Sun around this time about 75 degrees)
    Lat DR: 39 10N Lat Obs: 39 7N Lon: 61 50W

    May 7, 1823
    (Lunar lon listed but appears to be a "lunar acct" carried forward)

    May 8, 1823 #LUNAR#
    (gets no lat obs today but apparently does lunars right after noon)
    (Moon and Sun symbols) Obtained several sights at noon (times and implied longitudes) Mean 53 01W
    Lat DR: 34 04N Lat Obs: none Lon: 49 54W
    (elongation from Sun was about 35 degrees this date --waning)

    May 10, 1823
    Lat DR: 32 47N Lat Obs: 32 31N Lunar Lon: 42 55W  (based on previous day's account and D Lon the Lon DR today would have been 45 24W. So he updated his main account based on a lunar longitude --very unusual).

    May 11, 1823
    Lat DR: 32 31N Lat Obs: 32 28N Lon Lunar: 40 24W (since the D Lon is listed as 2 31 this is almost certainly a "lunar account" longitude --that is, a longitude from an earlier observation carried forward by dead reckoning. Also, the elongation from the Sun, at least, was only 6 degrees today so it could not have been an observation).

    May 12, 1823
    (some comments about depression and boredom and poor health followed by...)
    The Sun and Moon are not in distance. No Occultations are visible where we are so that we have no means of obtaining the correct Longitude. The observations taken in the preceding days were obtained under the disadvantage of squally weather. (...) Roast Chicken and Eggs for Dinner.
    Lat DR: 32 20N Lat Obs: 32 32N Lon by Lunar: 37 53W (again, by D Lon this is almost certainly a "lunar account" longitude)

    May 14, 1823 #LUNAR#
    Lat DR: 32 07N Lat Obs: 32 13N Lon: 36 04W (Lon doesn't make sense. by D Lon etc. it s/b 34 27W)
    Worked a Lunar Observation this Day. found the Longitude to be 30 20W. Vessel ahead of her reckoning.
    (elongation from Sun today about 50 degrees)

    May 15, 1823
    (he's depressed and bored)
    Lat DR: 32 13N Lat Obs: 32 14N Lon 28 59W (longitude has been updated by previous day's lunar)

    May 16, 1823  #LUNAR#
    Lat DR: 32 13N Lat Obs: 32 13N Lon 28 36W
    We this day took several distances of the Sun and Moon. the Longitude deduced therefrom was (...not recorded but from the following day's D Lon and Lon it would have been 28 59W. Elongation from Sun on this date would have been about 75 degrees)

    May 17, 1823
    Lat DR: 30 36N Lat Obs: 30 11N Lon: 28 27W

    May 19, 1823
    Lat DR: 24 17N Lat Obs: 24 03N Lon: 26 48W
    For 2 days past we have not been able to get a Lunar observation therefore the Longitude is merely by dead reckoning.

    May 21, 1823
    We lost the opportunity of measuring the Sun's altitude today through inattention (point being that its altitude would have been very close to 90 degrees at local noon on this day since they passed the Sun's declination during the 24 hours). We are fast advancing toward the parallel of the Cape Verde Island and shall pass within 2 degrees of them if our longitude by the last observation is correct.
    Lat DR: 18 41N Lat Obs: none Lon: 27 18W

    Jun 1, 1823
    We have not been able for several days to get a Lunar Observation but I have an idea that we are not far from the settlement at Sierra Leone on the African Coast.
    Lat DR: 5 23N Lat Obs: 5 13N Lon: 19 58W

    Jun 2, 1823 #LUNAR#
    (writer is sick and confined to bed. depressed. bored. Exaggerated handwriting. Incomplete navigational entries --no DR listed at all).
    Longitude by Lunar 20 06W
    Lat Obs: 4 49N Lon Lunar: 20 06W
    (elongation from Sun close to 90 degrees today)

    Jun 10, 1823
    (crossed the Line)
    Lat DR: 1 26S Lat Obs: 1 38S Lon: 23 00W

    Jun 13, 1823 #LUNAR#
    Lat DR: 7 43S Lat Obs: 7 43S Lon: 23 22W
    Long Lunar 24 49W
    (elongation from Sun about 60 degrees today)

    Jun 20, 1823
    At daybreak saw the Island of Trinidada called by seamen Trinity Island bearing SW distant 10 leagues and the Islands of Martin Vas bearing SE by S distant 15 leagues.
    Lat DR: 20 07S Lat Obs: 20 14S Lon: 25 27W
    (sighting of land indicates lon by acct was just about 3 degrees east of reality)

    Jun 22, 1823
    at noon we were abreast of Trinity Distant 4 miles from which we take our departure.
    Lat DR: 23 16S Lat Obs: 22 22S Lon: 28 27W

    Jul 5, 1823
    At 11 Oclock P.M. a meteor of uncommon size and brightness made its appearance to the NE so near us that the explosion was heard on deck very distinctly accompanied by a hissing noise like a rocket.
    Lat DR: 31 33S Lat Obs: 31 23S Lon: 0 47W

    Jul 10, 1823
    The water this day bore the appearance of soundings. being of the appearance of light green and our being in the latitude of the Cape of Good Hope and not having taken a Lunar for some time past could not be certain of our Longitude. We tried for bottom but could find none with 100 fathoms. God send us a quick passage around the Cape. Beef & Plumb Pudding Dinner.
    Lat DR: 35 58S Lat Obs: 35 30S Lon: 11 46E

    Jul 12, 1823
    (in a gale)
    We consider ourselves ahead of our dead reckoning. therefore we are to the eastward of the cape of Good Hope and consequently the wind from the Land. I wish we could get a Lunar Observation soon, but the vessel rolls so excessively and the objects being continually obscured by passing clouds we are not able to at present.
    Lat DR: 37 04S Lat Obs: 36 58S Lon: 18 20E

    Jul 14, 1823 #LUNAR#
    (after the gale)
    Lat DR: 36 58S Lat Obs: 36 59S Lon: 23 34E
    Longitude by a Lunar which we took today 24 14E
    (this was probably a Moon-Sun lunar. Elongation today 83 degrees)

    Jul 22, 1823
    (of various reefs charted in this area)
    However these dangers are scarcely to be depended on. there are several laid down under several different names as seen by so many different navigators. However the whole of them I suppose is no more than one seen in as many different Longitudes as their reckoning might very easily have been incorrect.

    Jul 23, 1823
    This morning the Moon set eclipsed so that we were disappointed in determining our Longitude from its Emmersion. No time for more remarks. Pancakes for Dinner.
    Lat DR: 37 40S Lat Obs: 37 35S Lon: 44 11E

    Jul 24, 1823
    Nothing material occurred. Crew employed at ship's duty. Saw several whales alongside. Gave W. Concklin lessons on Lunar Observations. Find that he progresses rapidly and I hope if we live to return I can assure his friends of his being a complete Lunarian. Beef Pudding for Dinner.
    Lat DR: 37 12S Lat Obs 37 12S Lon: 46 43E

    Jul 25, 1823  #LUNAR#
    We last evening obtained several distances of the Moon from the Star Antares. The mean Longitudes deduced therefrom was at 11:17 48 56E. From which point til noon (calculation of lunar account follows but slightly illegible concluding with 51 23E).
    Lat DR: 37 37S Lat Obs: 37 27S Lon DR: 50 06E
    Longitude by Lunar 51 23E from London
    (LD from Antares would have been about 85 degrees)

    Aug 7, 1823
    (spoke the Danish ship "Commodore Meyer")
    The Longitude of the Dane was 86 30.
    Lat DR: 34 51S Lat Obs: 34 53S Lon: 89 05E

    Aug 23, 1823
    This afternoon a drift of Bamboo passed us. No doubt from the Straits of Sunda. Fresh Bread for Dinner.
    Lat DR 12 54S Lat Obs 12 46S Lon 108 37E
    (there is no doubt that "Lon" is a DR acct since the "D Lon" values all match up from day to day)

    Aug 24, 1823
    Keep a sharp lookout during the night being near the Latitude of Moby or Christmas Island. Beef Pudding for Dinner.
    Lat DR 11 20S Lat Obs 11 19S Lon 109 32E

    Aug 25, 1823
    At 4PM saw Moby or Christmas Island directly ahead. towards evening came up with it. (...)
    Lat DR 10 33S (all other nav info dropped at this date and replaced with following)
    Longitude of the Island 104 22 (maybe? crossed out and written over with) 105 30
    Ship distant      4 W
    Longitude in      105 26 (something else crossed out, probably 104 18)
    We are now fully convinced from the circumstance of the great error of our reckoning in point of Longitude that we are are affected by a strong westerly current (...)

    Aug 26, 1823
    Lat DR 9 06S Lat Obs 8 55S Lon 106 13E
    (this Lon and the D Lon for today agree with my reading for the longitude of the previous day)

    Aug 27, 1823
    (in sight of land - Java - mentions various points, e.g. Pt. Haraf-bolong. Drops accounting of position altogether)

    Aug 28, 1823
    (coasting... no positional accounting except a latitude observation)
    Latitude by fore & back observation 7 12S

    Aug 29, 1823
    (still coasting...)
    At 7 saw Java Head bearing NE by N dist 4 leagues.

    Sep 13, 1823
    Left the schooner and entered on duty on board the Brig Indrimayoe as chief mate.
    (coasted around Java for two weeks slowly getting sick)

    Oct 2, 1823
    (author checks into Batavia Hospital)
    Schooner Weymouth sailed. (I suspect this is the unnamed schooner he sailed on from New York to Java).

    Oct 3, 1823
    Brig Indramayoe sailed.

    Oct 27, 1823
    (boarded the Brig Mars, bound for Amsterdam)

    Nov 1, 1823
    At 4 AM weighed anchor from Batavia roads for Amsterdam.

    The return journal entries are much less interesting navigationally so I have not bothered with them. This journal, by the way, is the one that contained the raw lunar calculation that I described on the list a couple of days ago. The lunar observation in question is for March, 1825 so it's not directly relevant to the entries above.

    Frank R
    [ ] Mystic, Connecticut
    [X] Chicago, Illinois
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