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: sextant index error measurement
    From: Frank Reed CT
    Date: 2006 Nov 9, 03:57 EST
    "I checked with a friend who worked in Arizona.  He said he had a
    "clear mental image of a range pole at a half mile looking like
    a snake through the transit", and that the more important angles
    were shot in the morning.  But . . . they kept working.
    Probably depends on the accuracy you need."
    Sure. As I've said previously, the 'normal' terrestrial refraction ranges from 0.1 to 0.5 (or so) minutes of arc per nautical mile. That's why you can only trust the dip of the horizon to about that level of accuracy. But for a few hundred feet, as in the laser test we've been discussing, the terrestrial refraction is about ten times smaller. And that's just the absolute refraction. For two beams side-by-side, the differential refraction is smaller again, by an order of magnitude. In short, it doesn't matter ...under these specific circumstances.
    42.0N 87.7W, or 41.4N 72.1W.

    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@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