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: Pre Calculating (Hp) For Fixed Angle Reflectors
    From: Fran Herranz
    Date: 2018 Jun 4, 18:19 +0200
    I had readed this list for years and Bris "sextant" is the reason. I have been thinking a lot about use it easily with simplified tables. Probably the ideas I explain afterwards are only a summary of all I read here.
    I assume that is related to the improved number of angles Bris like sextant discussed now in other topic.
    Are you proposing a Pub 229 or 249 like tables for every Bris angle? Maybe a lookout table organized in a page for every Bris sextant's angle with assumed latitude in columns, declination in rows that gives LHA and two azimuth (East and West of the meridian)like result. It could be generated after calibrate Bris sextant's angles and would be printed in a tiny booklet.
    You only wait for time when object hits horizon. With the difference between tabulated time and actual time you could move the tabulated LoP.
    Maybe for standard Bris or a non shaded Bris microscope slide for Moon needs the full range of declinations but for mirror star Bris (two fixed angle mirrors) you need to calculate only for several declinations as many as nautical stars.
    I made time ago a spreadsheet for some angles and declinations.
    P.S.: Sorry for my English and for so large boring speech.
    Fran Herranz

    El dom., 3 jun. 2018 19:37, Greg Rudzinski <NoReply_Rudzinski@fer3.com> escribió:

    A general question...are precalculated Hp altitudes for a fixed angle reflection (such as the Bris sextant) plotted from an assumed position that is shifted in longitude by the observed time difference converted to arc ? Is the time sight formula to be used for the precalculation ?  

    Greg Rudzinski

    View and reply to this message

    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