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
    Name or NavList Code:
    Email:
       
    Reply
    Re: Finding stars in daylight
    From: Fred Hebard
    Date: 2019 Jul 14, 21:22 -0400
    John,

    The tilt great circle would be a tilt of the great circle that passes through the location of the telescope and the zenith.   It would be at right angles to the direction of tilt.  The tilt great circle would no longer pass through the zenith; most don’t.  The latitude of its apogee would be zenith - tilt. Rotating that puppy to change azimuth is the next trick.  The latitude of the apogee of a rotated tilt great circle would remain the same.

    Fred

    Fred Hebard



    On Jul 14, 2019, at 15:01, John D. Howard <NoReply_Howard@fer3.com> wrote:

    Fred,

    I do not know a good formula either, but thinking about the geomertry of a telescope's motion will give you some limits.

    If your scope is pointing east, but the horizontal axis is tilted one degree left down, your true azimuth is east.  As you raise the scope in eleavation without turing the the yoke along the vertical axis the line of sight azimuth will slowly look north of east.  At 90 degrees elevation it will point one degree north of your zenith or 89 degrees.  The line of sight will not be a great circle.  A great circle must go through your zenith and the center of the earth. Your line of sight will go one degree north of your zenith to one degree south of the center of the earth.

    The point is that the azimuth at any elevation will not be off more than the tilt of the horizontal axis.  This will be true for whatever the zero degree azimuth is.  The error will always be in the direction of the lower side of the horizontal axis.

    John H.    41N  100W


       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a 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