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: An azimuth nomogram: what's under the hood?
    From: Tony Oz
    Date: 2018 Mar 13, 03:31 -0700

    Dear Sean and Gary,

    Thank you for the feedback.

    I should have made the translation myself. The nomogram is called "A celestial body's rise and set semi-circular true azimuth".

    The left wing of the parabola has the "Latitude of observer" label, the vertical scale has the "Declination of celestial body", the right parabola's wind has the "Rise (set) azimuth if same-name φ and δ" label on the inner side and the "Rise (set) azimuth if contrary-name φ and δ" label on the outer side.

    The comment below the nomogram is "When observing from the sea level - the center of the celestial body is on the plane of horizon if: - Sun's lower limb is over the horizon at 0,7 of its diameter; - Moon's upper limb is at altitude ~0°; a star or a planet is at 0,5° altitude (a Sun's diameter)".

    The rest of the text is translated correctly.

    So, back to my initial questions.

    I wonder why the nomogram is based on the parabola?

    I wonder how could I re-calculate positions of each and every angular mark along each scale?



    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