Old World Maps\Astronomy

Discussion in 'Science' started by .AQL., Mar 4, 2017.

  1. .AQL.

    .AQL. Member

    Joined:
    Jun 15, 2003
    Messages:
    87
    Location:
    Cairns
  2. sebbyreddan

    sebbyreddan Member

    Joined:
    Jan 28, 2009
    Messages:
    33
    Location:
    Cairns
  3. RobRoySyd

    RobRoySyd Member

    Joined:
    Jan 24, 2008
    Messages:
    7,751
    Location:
    Sydney
    Yes, it's the path of the Sun. The clue is the inclination matches the tropic of Cancer - Capricorn.
     
  4. .AQL.

    .AQL. Member

    Joined:
    Jun 15, 2003
    Messages:
    87
    Location:
    Cairns
    OK thanks.

    Now if that's the path of the Sun then why do we not draw a straight line down the dead centre of those two curves to form a non-arbitrary prime meridian rather than the random one we have at the moment which is further to the east closer to Africa?
     
  5. RobRoySyd

    RobRoySyd Member

    Joined:
    Jan 24, 2008
    Messages:
    7,751
    Location:
    Sydney
    That's probably what however drew the map thought it was but it's not. Over a 24 hour period the Sun is always going to be over one parallel of latitude.


    Every meridian is the same, any prime is always going to be arbitrary.

    Don't get confused by those Mercator projections of the Earth that may depict areas of nigh and day.

    https://www.google.com.au/search?q=...=nJK6WJv_BoSp0ASQ7qy4CQ#imgrc=CSPF-1wIfgzv3M:


    The sinusoidal shape is due to the inclination of the Earth in the direction of the Sun. Six months later it reverses, it's still arbitrary.
     
  6. mtma

    mtma Member

    Joined:
    Aug 12, 2009
    Messages:
    4,334
    Interesting, the map depicts both Ptolemy's and Copernicus' theories about the solar system and is dated 1660. Considering it's not long after church went and condemned Galileo for his views.
     
  7. RobRoySyd

    RobRoySyd Member

    Joined:
    Jan 24, 2008
    Messages:
    7,751
    Location:
    Sydney
    Update - Correction.

    The mystery line is The Ecliptic.

    I guess what the map maker has done is to project the celestial sphere onto the Earth?
     
  8. shredder

    shredder Member

    Joined:
    Dec 26, 2001
    Messages:
    9,196
    Location:
    Dec 27, 1991
    Last edited: Mar 5, 2017

Share This Page