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
    Hughes, Dreisonstok and dec~lat
    From: David C
    Date: 2020 Apr 13, 14:58 -0700

    The lockdown is giving me time to study various tables in detail. For example, I have learned that Aquino (HO 200) allows use of the DR position rather than requiring an asumed position. The same applies to Ageton (HO 211).

    I took several sun sights and decided to reduce them using Hughes' tables. The first step was to learn Hughes'  method. After I had successfully worked one sight I performed sanity checks with AP3270 (HO249), HD486 (HO214), NP401 (HO229) and the cos formula.  Then I decided to try HO 208 Dreisonstok. I found that these tables are similar to Hughes' but with one big difference -  the meaning of dec ~ lat.

    Back on 21st  June 2016 Franks wrote   (dec ~ lat) = abs(dec - lat).

    The worked examples given in the tables show that

    Hughes   K~d = abs(K-d)

    Dreisonstok   d~b = abs(d+b)

    I have  worked the same sight with both Hughes' and Dreisonstok and can confirm these conventions.

    With reference to d~b, page  69  of Dreisonstok states    ".......add if the signs are alike, subtract if unlike." 

    DavidC

    File:


    File:


       
    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