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
    Re: Accuracy of sextant observations at sea
    From: Greg Rudzinski
    Date: 2010 Nov 25, 12:02 -0800


    You asked "What sort of boat or vessel are sextant shots made from?"

    For starters:
    1. Super tankers to canoes.
    2. Submarines
    3. Airplanes
    4. Blimps/Balloons
    5. Space craft
    6. Car/Truck
    7. On foot

    Probably not from a jet ski though ;-)

    "What sort of accuracy can be reasonably expected"

    Having done both small craft and ship CN I would say that 3NM is good aboard a sailboat and 1.5NM is good aboard ship. This is subjective opinion based on experience.

    To get 3NM accuracy aboard a sailboat it is best to average four or more observations. To get 1.5NM accuracy aboard ship I found that averaging was not necessary. It is always good practice to spend a few more seconds of time to swing the arc so as to be sure of perpendicularity of the sextant to the horizon.

    "How experienced is the shooter"

    Experience helps with sextant adjusting, observations, sight reduction, and plotting. Practice makes perfect. There is a point somewhere along the line when major blunders are routinely avoided. Subtle blunders are more difficult to discover but can be reduced also with practice.

    Just like calling shots in marksmanship you will be able to call your shots with the sextant too.

    Greg Rudzinski
    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