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: DIY Tables?
    From: Greg Rudzinski
    Date: 2015 Aug 28, 13:28 -0700


    Good catch for February 2020. Add 20 hours following leap day. All I did was to extrapolate forward then do a check against USNO to confirm correction. This table doesn't need to be perfect. rounding to the nearest hour is good enough. You will see that there is 25 hours difference between 1988/1992, 2000/2004,2008/2012. I'm not sure what the rule is for this so I just work up a sight for the future date in question to make sure results are close.

    Greg Rudzinski

    From: Herman Dekker
    Date: 2015 Aug 28, 06:29 -0700

    Hello Greg,

    I see the extended Table 4 Year correction, the correcxtion is to year 2028.

    I understand is that in a year when februar has 29 days after the 29 you have to use the * correction.

    In your handwritten correction after the 29 it is 25 hours more. In the original table from 1981 until 2016 it is

    always 24 hours more. Can you explain??

    NB. the correction for 2020 after 29 februar is missing, I suppose it must be +20* (or +19*???)


    Herman Dekker

    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