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: Getting to know a sextant.
    From: Bob Crawley
    Date: 2017 Mar 1, 11:32 -0800

    Frank - that was an interesting point you made which got me digging. From what I can gather from Wikipedia Annual aberration is around 20 arcseconds and the stars appear to move in circles at the poles (I suppose this could be a a change in SHA or DEC) and lines on the equatorial plane (i.e. a change in SHA). As you say this would make an interesting test to measure the interstellar angle at different times of year, perhaps with one star with high DEC and one with low. I think I'll figure out how to mount my sextant on a tripod (also good for Lunars I expect).

    I then started comparing this with the monthly 173 stars in the Almanac and the figures are much bigger. I presume that this is due to Precession which accounts nearly an 1 arcminute per year. Is that correct or have I misunderstood?

    Regards

    Bob

       
    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