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
    Re: Ephemerides at Columbus' Time
    From: Craig Levin
    Date: 2012 Oct 25, 10:51 -0700


    I'm putting together a planetarium show on Tycho Brahe that should be ready in the spring. Kepler worked with Brahe when Brahe was in Prague, in the last years of his life. Were it not for Brahe, Kepler wouldn't have had pages & pages of observations of Mars to allow him to derive his 3 laws of planetary motion.

    The situation before Brahe's work was pretty sad. Many astronomical constants hadn't been checked for their accuracy since the days of the Greeks. Brahe's table for refraction was one of the first that came close to accuracy. If I might venture a guess about why Columbus & other early explorers had such a sad record in celestial navigation, it's as much a result of inaccurate work by the writers of the ephemerises as anything else. For instance, a predicted conjunction of Jupiter & Saturn was days off from the actual event. Even the position of the Sun wasn't always accurate.


    > Brad -
    > Yes indeed....honest to god ephemerides produced by Regiomontanus,
    > Copernicus, and Kepler. He even has some teaching texts with marginal
    > notes in Copernicus's handwriting. Yes, he even lets me touch them.
    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

    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