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: Interpolation to latitude
    From: Joe Schultz
    Date: 2009 Nov 15, 23:45 -0800

    And back to Inuik's topic.
    
    Thank you Peter!  The nearest complete paper nautical almanac is about 250 Smi 
    from me.  Thanks for going to the source.  For the novice, Peter's final 
    quote is how most of us operate - sometimes the assumptions become too 
    automatic.
     
    Inuik, looks like you understand the longitude correction (but I'm not too 
    sure who Jerry is - hee hee).  This type of exercise is good for much more 
    than planning a round of sextant shots.  Let's work one more practical 
    example.
    
    Exercise: you are planning a day of fishing, in the Gulf of Mexico off 
    Yankeetown, Florida, and want to return and trailer the boat before dark.
    Find: sunset 28JUN2010 at N29d W82d45m.
    Almanac data (via USNO website): sunset N30 = 1905.  N20 = 1843.
    Answer (in local zone): ZT = 1843 + 20m - 29m = 1834 "S" 28JUN2010 = 0034 "Z" 29JUN2010.
    Answer (in GMT/UT): ZT = 1843 + 20m + 5h 31m = 0034 "Z" 29JUN2010 = 1834 "S" 28JUN2010.
    
    Bonus for the North American readers: your helper lives in Yankeetown.  When 
    (by his watch) does he need to be at the boat ramp with your trailer?
    Answer (in local zone): 1834 + 1h + 1h = 2034 "R + DST" or 8:34PM EDT 28JUN2010.
    Answer (in GMT/UT): 0034 - 6h + 1h + 1h = 2034 "R + DST" or 8:34PM EDT 28JUN2010.
    
    This is a real place with a real boat ramp.  And, as promised, why is it OK to 
    apply a linear interpolation for the LAT CORRN?
    
    Derrick, an interpolation is a mathematical process where you find an unknown 
    value between two other known values.  In and of itself, an interpolation has 
    no physical meaning.  That's not the answer, by the way - it's a start in the 
    thinking process.  I see the "mil" in your address - thanks for serving.  
    Bluejacket, sandcrab, wingnut, or one of the mudsucker flavors?
    
    Joe
    
    
    
    --~--~---------~--~----~------------~-------~--~----~
    NavList message boards: www.fer3.com/arc
    Or post by email to: NavList@fer3.com
    To unsubscribe, email NavList+unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    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