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
    Aldebaran occultation
    From: Alexandre Eremenko
    Date: 2017 Mar 5, 05:14 +0000

    This evening I observed Aldebaran's occultation by the Moon.
    I had to use a binocular (8x30) because Aldebaran was obscured by the Moon light and
    not visible with the naked eye since about one hour before the occultation.
    The moment of disappearance I timed as March 5, 3:56:48 (GMT)
    using a stopwatch started from the GMT web site. The disappearance was sudden, 
    very sharp, as a lamp switched off,
    and I am sure that I timed it correctly.
    Then I entered the data to Frank's online calculator
    40d27.2'N, 86d55.8'W
    IC 0
    Distance: 0, near limb.
    To my surprise I obtained the error -0.2' in the distance.
    Playing with the calculator shows that it gives zero distance for the time from 3:57:52 to 3:58:36,
    which is more than 1 minute later than I observed.
    How to explain this disagreement? 
    The re-appearance is more difficult to time, again because of the Moon light obscuring the star.
    When I noticed it it was about 4:39, but it was already at some visible distance from the Moon surface.
    Frank's calculator shows that reappearance happened between at about 4:36.

    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