Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Trans-Atlantic Crossing
    From: Antoine Couëtte
    Date: 2012 Nov 8, 05:34 -0800

    RE : [NavList] TRANS-ATLANTIC CROSSING
    From: Kevin Coulombe
    Date: 22 Oct 2012 15:51
    BODY: stars

    *******

    From Kermit : solving here-under your fix, Kevin. Hopefully I correctly "decoded" your data. Computations performed with TT-UT = 68.0s

    *******

    Date: 22OCT2012 LT - WATCH TIME: as per body - ZD: +4 - WATCH ERROR: 5S FAST

    SEXTANT - FPM DRUM SEXTANT / AP MOLLER COMPANY ISSUE / CURRENT BRIDGE EQUIPMENT
    4X40 MONOCULAR - RESIDUAL ERRORS +5” AT 20 DEGREES - INDEX ERROR 0.8 OFF THE ARC

    HEIGHT OF EYE 30 METERS - BAROMETER 1013 - AIR TEMP 15C

    DR L 41 00 N Lo 066 30W Note from Kermit : this DR position is assumed to be the one valid for LT = 18:12:05 (Hour of the MIRFAK Observation. If it were not the case, the final observed position for the chosen LT remains unchanged anyway). Course 076 T Speed of Advance 21.2 kts .

    BODY
    MIRFAX
    WT 181440 UT = 22h14m35.0s
    Hs 18-40.2 H = 18°41'0 Corrected for Index error but NOT for "residual error at 20°" i MIRFAK = +1.2 NM (T), Z Mirfak = 038°9

    ALTAIR
    WT 181210 UT = 22h12m05.0s
    Hs 58-06.5 H = 58°07'3 Corrected for Index error but NOT for "residual error at 20°" i ALTAIR = +2.7 NM (T) Z ALTAIR = 180°8

    ARCTURUS
    WT 181623 UT = 22:16m18.0s
    Hs 15-57.3 H = 15°58'1 Corrected for Index error but NOT for "residual error at 20°" i ARCTURUS = -6.9 (A) Z Arcturus = 281°8

    MOON
    XXXXX
    XXXXX
    Technical error: I should have shot this body late in civil twilight as by the time I shot the moon the horizon was too dark.

    OBSERVED POSITION from DR in Azimuth 116° at a distance of 6.9 NM
    LOP's Dispersion : 0.3 NM (excellent)

    At 18:12:05 LT , DR Position : N 41°00.0' W 066°30'0 , and
    Observed position : 40°56'9 W 066°21'8

    Note : this position is close from the one derived by Greg : N4°57' W066°23' probably for that same 18h12m05s LT.

    *******

    Thank you very much Kevin, for giving us the opportunity of crunching real world numbers. The quality of your fix seems really good.

    BTW, what was the GPS fix at that time, or any time close to 18h12m05s LT ? If you have it on file (both Position and Time), then you could quite reliably "grade/rate" the quality of your CelNav Fix from GPS position, especially as far as your Observed Longitude is concerned. Latitude should be no problem.

    Best Regards to all

    Kermit
    ----------------------------------------------------------------
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com
    ----------------------------------------------------------------

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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