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
    Need dip-throw a rock?
    From: Bruce J. Pennino
    Date: 2011 Jun 20, 11:43 -0700

    I considered the same problem recently on a bluff (high dune) on Cape Cod. Most states have topo maps on-line, and you can get an elevation above MSL from the map. Close enough for a me....only a beginner and still have not purchased a sextant.

    Further ,once you get above 30-40 ft, dip does not change too much per 10 ft.
    Dip = 6.1' @ 40ft; 6.9'@ 50 ft; 8.7' @ 80 ft . Someday I'll worry about refinements.

    Regarding free falling stone (dense object) in normal atmospheric conditions, no flutter, rotation, or any other special conditions, my calcs show

    y -ft t-time sec Dip (more or less) min.

    20 1.1 4.4
    40 1.6 6.3
    80 2.2 8.9
    120 2.7 10.6

    or dip is about 4 * free-fall seconds.

    Bruce Pennino
    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]fer3.com

    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