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
    or...
       
    Reply
    Re: Time of Sun & Moon rise and set
    From: Brad Morris
    Date: 2016 Feb 4, 17:31 -0500

    Hello Steve

    There are two meridian transits available at high latitudes.  They are termed the upper and lower meridian transit. 

    The upper meridian transit corresponds directly to the meridian you are on.  The lower meridian transit corresponds to a meridian 180° away from the meridian you are on. 

    There is a singularity directly on the poles since you are simultaneously on all meridians at the same time!  So just arbitrarily pick one.  The nominal time zone in polar navigation is GMT (Dutton, para 4213).

    Your specific question was do we adjust the time of meridian crossing as a function of latitude, specifically at higher latitudes.  Both of the other respondents are correct.  You do not. 

    You are correct that we must adjust the time of rise and set as a function of latitude.  Consider, in high latitudes the sun may never rise or set in a 24 hour period.  Stars at high declination never rise or set when observed from high latitudes.  Yet the opposite is true at the equator, where all bodies rise and set on a roughly 12 hour cycle.

    Brad

    On Feb 4, 2016 1:34 PM, "Steve E. Bryant" <NoReply_Bryant@fer3.com> wrote:

    Dear NavListers,

    For purposes of determining time of sun rise and set, I understand it is important for adjust time according to your latitude (and of course longitude); but, is it necessary to make adjustments based upon latitude when determining meridian transit?  I suspect not; nevertheless I ask the question particularly with respect to the extremes as you approach the poles.

    Steve Bryant

     

    View and reply to this message

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting 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