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: Digital Image CN Exercise
    From: Greg Rudzinski
    Date: 2010 Apr 14, 04:28 -0700


    I,m using a vintage Pentax Super Takumar fixed 200mm for my digital image CN exercises and by trial and error have found the sweet spot for sunset photos above 2 degrees. The problem has been overexposure. The solution seemed to be a pair of circular polarizers but this caused distortion when held at the front of the lens. The better solution has the circular polarizers held out in front of the lens as far as possible. This somehow has greatly reduced distortion. The linked image settings are f16, 1/1000s, ISO 100, B&W, in manual mode. The resulting intercept is a respectable 0.6 NM.

    When you get the chance try taking some telephoto images through your whole horizon Plath using the camera clock as a chronometer. Determine the minutes of arc per pixel for the lens with the Sun's diameter (from high altitude) as reference then count pixels to the nearest limb. This technique works well enough to consider a digital camera scope attachment as an interesting sextant accessory option.


    NavList message boards and member settings: www.fer3.com/NavList
    Members may optionally receive posts by email.
    To cancel email delivery, send a message to NoMail[at]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