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: sight reduction tables
    From: Marc Bernstein
    Date: 2007 Sep 28, 18:54 -0400

    On 9/28/07, George Huxtable  wrote:
    
    > Of course, HO 249 achieves its condensation by sacrificing precision,
    > working only to 1 minute instead of 0.1 minutes. And that allows the chosen
    > stars to have fixed positions, whereas aberration alone can shift some stars
    > by up to 0.3' each way, over a year. But it leaves another question in my
    > mind. How does HO allow, for its named stars, for the slow drift in star
    > position caused by precession? Is there some way provided of correcting for
    > this drift, year on year? Or is Vol 1 of HO249 reissued after a period, when
    > precession starts to put star positions unacceptably far out?
    >
    
    Exactly! An updated edition of Vol 1 is published every 5 years. The
    Epoch 2010.0 edition, as they call it, should be out shortly.
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to 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