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: Lunar eclipses and other things
    From: Lisa Fiene
    Date: 2004 Oct 27, 13:29 +1000

    Alexandre,
    
    This is so interesting.  Shall have to read the thread on Wulf's grid.
    
    Following is a quote from DON QUIJOTE OF LA MANCHA, which I love....
    
      "And if I had here an astrolabe to take the
    altitude of the pole, I could tell thee how many we have travelled,
    though either I know little, or we have already crossed or shall
    shortly cross the equinoctial line which parts the two opposite
    poles midway."
    
       "And when we come to that line your worship speaks of," said Sancho,
    "how far shall we have gone?"
    
       "Very far," said Don Quijote, "for of the three hundred and sixty
    degrees that this terraqueous globe contains, as computed by
    Ptolemy, the greatest cosmographer known, we shall have travelled
    one-half when we come to the line I spoke of."
    
    "Don Quijote of La Mancha" (Cervantes) Chapter XXIX
    
    All the best,
    Lisa
    
    Alexandre Eremenko wrote:
    > Lisa,
    > I found a confirmation to you hint that I interpreted
    > as the "rete was engraved with a STEROGRAPHIC projection
    > of the celestial sphere".
    >
    > It is in Cotter's "History of nautical astronomy".
    >
    > So now I understand how the device worked!
    > It was based on the same principle as the
    > "Wulf's grid" which I mentioned once on this list
    > Sun Oct 17 2004 - 00:44:05 EDT
    >
    > Planispheric astrolabia was indeed an instrument
    > combining angle-measuring device, almanac and computer.
    >
    > On its history Cotter writes:
    >
    > "The great Hypparchus is usually credited with the
    > invention of planispheric astrolabe...
    > If, in fact Hypparchus did invent is, the instrument
    > of his invention could have been but a primitive form
    > of the complex astrolabes of a later age.
    > It is to the astronomers of India, Persia and Arabia that
    > honor is due for the perfecting of the planispheric astrolabe".
    >
    > In this account he apparently misses the period when
    > Theon and his daughter Hippatia worked. (This was a relatively
    > short period of aborted renaissance of science in Alexandria
    > that followed the decline caused by the Roman invasion,
    > and ended soon after Hippatia's death, with the coming of
    > the Dark Age, when practice of science was completely interrupted
    > in the West).
    >
    > Then he explains that this instrument was not for navigation
    > but an "astronomer's piece". And the mariner's astrolabe
    > was a much simplified instrument designed to take altitudes
    > only.
    >
    > Alex.
    >
    >
    
    
    --
    Kind regards
    Lisa Fiene
    ***************************
    
    CopyCare Pacific Pty Ltd
    Lizard Tunes
    ABN 93 101 046 888
    PO Box 314 Ourimbah NSW 2258
    Australia
    Phone/Fax: (02) 43 627 583
    International: 61-2-43 627 583
    E-mail: lisa{at}copycarepacific.com
    Web: www.copycare.com/content/local/ccpaceng.asp
    
    
    

       
    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