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: Average altitude of a celestial sight
    From: Frank Reed
    Date: 2020 Aug 17, 15:30 -0700

    I'll try this again. What is the average altitude of a star? Let's ignore limitations on visibility and assume that we can see all stars from 0° to 90° altitude. Everybody's first guess is 45°. But that can't be... There are many more stars below 45° altitude than above 45°.

    Consider the 57 navigational stars. They're evenly-spaced around the celestial sphere. From a random location at a random time of night, half of them, 28.5 on average, will be above the horizon. Of those, on average about 20 will be below 45° and 8 will be above 45°. An average sextant altitude will necessarily be below 45°. So what's the actual average? 

    Frank Reed

    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