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
Add Images & Files
    Name or NavList Code:
    Email:
       
    Reply
    Re: Position fix by visual satellite pass
    From: Antoine Couëtte
    Date: 2023 Aug 3, 12:01 -0700

    From the Observer's Position (here Scotland Neck, NC) and given the geometry involved - with the apparent ISS track intercepting Vega apparent vertical zenith at an angle close to 46° - interesting to see that if you proceed 6 NM towards Vega, it will "raise" Vega by 6' over the new local horizon, and the apparent ISS track will become "closer" from Vega by 1°.

    In other words, if one can estimate such apparent Minimum distance of the "ISS track" from the picture (BTW beautiful Virginia Tulip Tree /  Liriodendron Tulipifera, no ?) to +/- 0.1° which seems realistic - I have made it at 4.8° - the uncertainty on ground of the "ISS Lop" should remain under 1 NM.

    Since the Vega Lop is accurate to also better than +/- 1 NM, this explains why the geometry of the problem significantly narrows down the end result uncertainty which, even with the current GDOP, should remain under 2 NM.

    And as regards your post immediately here-under, YES, please be so kind as to publish your own comments.

    Thanks again,

    Kermit


    Re: Position fix by visual satellite pass
    From: Frank Reed
    Date: 2023 Aug 1, 10:48 -0700

    I'll get back to methodology later today (and bug me if don't!), but to honor your efforts: yes, Scotland Neck, NC. That's where the observer was located. 

    Frank Reed

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    NavList is a community devoted to the preservation and practice of celestial navigation and other methods of traditional position-finding. We're a group of navigators, navigation enthusiasts and hobbyists, mathematicians and physicists, and historians interested in all aspects of navigation but primarily those techniques which are non-electronic.

    To post a message, if you are already signed up as a NavList member, start a new discussion or reply to any posted message and use your posting code (this is a simple low-security password assigned when you join). You may also join by posting. Your first on-topic messsage automatically makes you a member, and a posting code will be assigned and emailed to you for future posts.

    Uniquely, the NavList message boards also permit full interaction entirely by email. You can optionally receive individual posts or daily digests by email, and any member can post messages by email (bypassing the web site) by sending to our posting address which is "NavList@NavList.net". This functionality is similar to a traditional Internet mailing list: post by email, read by email, reply by email. Most members will prefer the web interface here for posting and replying to messages.

    NavList is more than an online community... more about that another day.

    © Copyright notice: please note that the rights to all messages and posts in this discussion group are held by their respective authors. No messages or text or images extracted from messages may be reproduced without the explicit consent of the message author. Email me, Frank Reed, if you have any questions.

    Join / Get 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