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
    Name or NavList Code:
    Email:
       
    Reply
    Re: Regulus Occultation, unexpected results
    From: Sean C
    Date: 2017 Sep 30, 17:52 -0700

    Antoine,

    You wrote:

    "These deltaT values are not super accurate for our contemporary period, but they relieve you from having to search real values each time from the Web."

    In case you weren't already aware, anyone can register with the IERS here and select various bulletins to receive via email. (I currently receive bulletins A and C: ΔT and leap second announcements, respectively.) This saves you from having to search for anything - the ΔT values are right there waiting for you in your inbox each week. Also, bulletin A contains predictions for an entire year from the date they are published, so you can save them for offline use for that time period or even paste them into a table for program lookup. Of course, these are predictions and may [will] be in error, but the error will almost certainly be much smaller than that obtained using the polynomials on the NASA website.

    Speaking of bulletin A, Paul Hirose recently wrote:

    "The correct value can be determined from IERS Bulletin A, which says UT1 - UTC = 0.32604 s at 0 h on that date. Thus delta T = 32.184 + 37 - 0.32604 = 68.9 s."

    I am curious as to where Paul got his figure, because "my" copy of bulletin A, vol. XXX Nº. 37 (and the one on the IERS website) show a value of 0.32558 s for UT1 - UTC on Sep. 18th. Of course, this is only a 0.00046 s difference and would have no impact here, but I am curious, nonetheless.

    Regards,

    Sean C.

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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