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
    Name or NavList Code:
    Email:
       
    Reply
    Re: Basics of computing sunrise/sunset
    From: Greg Rudzinski
    Date: 2009 Jun 17, 16:41 -0700

    Christian,
    
    Even though the altitude is negative enter it into the formula as
    positive. Add the second part of the formula if latitude and
    declination are the same name(north or south) and subtract if
    contrary. Be sure to apply the equation of time in the correct
    direction and the same goes for the arc to time correction for the
    angular difference between the longitude of the observed sunset and
    the time zone meridian. If sunset is before 1800 LMT add 180� to the
    formula angle. If sunset is after 1800 LMT subtract the formula angle
    from 360�. Dip is also a factor to corrected for.
    
    Greg
    
    
    
    On Jun 17, 1:41�pm, "Christian Scheele"  wrote:
    > I'm trying to solve the following sunrise/sunset astronomical triangle and
    > am encountering unexpected pitfalls.
    >
    > cos(LHA) = [sin (a) - sin (lat) sin(dec)]/ cos(lat)cos(dec)
    >
    > where I am assuming a = -0.83 degrees
    >
    > It is of course something very basic and I'm almost embarassed to say that
    > although I keep rechecking what I'm doing, I remain with an error of about
    > 15 minutes by the time I get to the final result in mean zone time. Before I
    > drag everybody into it, could somebody please tell me whether there are any
    > snags that I should look out for?
    --~--~---------~--~----~------------~-------~--~----~
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To , email NavList-@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

    Enter the email address associated with your NavList messages. Your NavList code will be emailed to you immediately.
    Email:

    Email Settings

    NavList ID 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