Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Baffled by Baffin
    From: tony
    Date: 2005 Nov 23, 16:56 +0000

    I have been reading the ?Voyages of William Baffin? (Hakluyt Society), but
    am having a problem with the description of his initial attempt to find his
    longitude on the west coast of Greenland (pp 20 & 21). Putting aside the
    shortcomings of the lunar culmination method,  his data and description
    suggest that he saw the moon as outstripping the sun in its daily passage
    around the earth.
    ?Thursday, the ninth day, very early in the morning, I went on shore the
    island, being a faire morning, and observed till the moone came just upon
    the meridian. At which instant I observed the sunne?s height, and found it 8
    51.? He then goes on to describe that by the use of spherical trignometry
    involving his latitude, the sun?s declination and the sun?s altitude, he
    found the sun?s local hour angle. Converting this to local time, he found
    the time of the observation to be 4h 17m 24s.
    My problem is what follows next. ?Which when I had done, I found by mine
    ephemerides, that the moone came to the meridian at London that morning at
    4h 25m 34s which 17 minutes 24 seconds subtracted from 25minutes 34 seconds
    leaveth 8min 10secs of time for the difference of longitude betwixt the
    meridian of London (for which the ephemerides was made) and the meridian
    passing by this place in Groenland.? He then describes the moon?s motion
    that day as 48mins and 29 secs and describes it as ?the time that the moone
    commeth to the meridian sooner that day then she did the day before, give
    360, the whole circumference of the earth; what shall 8 minutes 10 seconds
    give, to wit 60 degrees, 30 minutes.?
    Has anyone else seen this and can they offer any explanation. Baffin writes
    with much clarity and the problem does not arise elesewhere in his account.
    As his pioneering attempt to measure longitude was so very far out, I have
    wondered if he looked up the wrong data in Searle?s Ephemerides.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site