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: The Star of Bethlehem and Navigation
    From: Michael Dorl
    Date: 2009 Jan 03, 20:42 -0600

    frankreed{at}HistoricalAtlas.com wrote:
    > By the way, the introductory web page shows an example of an ancient 
    astronomical observation (the most ancient?) that puts a strong constraint on 
    delta-T: the solar eclipse of March 5, 1223 BC seen at Ugarit in Syria. If we 
    have records stating that an eclipse was seen from a specific place, all we 
    need to do is change delta-T by trial and error until the eclipse path 
    crosses the observer's location. The catch in this case is that the tablets 
    recording the eclipse aren't dated. So you need some other information to 
    narrow the date to the nearest century or two.
    >
    > -FER
    >
    >   
    I start up my almanac program and put in the lat/log of Ugarit (35.8E 
    35.683N), set the date to 3/5/1223 BC and play with the time until I get 
    the lunar distance of the sun as low as possible at 1152.  I then have a 
    separation of 4' 9.3".  I diddle delta T which my program has set to 
    28404.763 and find I can get a closer approach at 11:50 with a delta T 
    of 28460.000.
    
    So what am doing when I diddle delta T?
    
    The picture I have in my mind is a sphere with the path of the eclipse 
    outlined on it with an overlay sphere with a map of the world on it.  So 
    by changing delta T I  revolve the map about the earths axis  relative 
    to first sphere to bring Ugarit closer to the center of  the path of the 
    eclipse.   So delta T is constrained to those values which bring Ugarit 
    into the path of the eclipse.
    
    Is that an ok way to think about it? 
    
    Hopefully my almanac has also made some reasonable adjustments for 
    changes in the earths axis.  Are those know well enough and predictable 
    enough to project them 3000 years into the past?
    
    Mike
    
    --~--~---------~--~----~------------~-------~--~----~
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@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