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: I got an eclipse
    From: Mark Coady
    Date: 2017 Aug 21, 15:27 -0700

    I recall that the optimum range for Lunars was 45 -110 degrees, with a note that below 20 degrees there were math problems.  I know part of it extended from the accuracy of altitudes taken  based on the relation of Sin (LD)  and Tan (LD) functions to the Cos of the altitudes.

    With these very short lunars, other than with a computer calcualted altitude feature, would this normally be used?  even though the denominator around 60 degrees is nice, the numerator starts to demand high precision. It looks as if the altitude accuracy would be in the neighborhood of .1' along with the required lunar distance.  Of course if you needed a lunar on the new moon....what else can you do. 

    Is there perchance and illustration of how the phase method produces an LOP mathamatically?  I get the concept in that that relationship can only exist on a specific view cone, but I'm not picking up the first hint on how to specifically calcualte it.

    Also, I took a decent shot of the clipse through my 7x scope on my Sextant using my cell phone. Thats an interesting juggling act.  Fortunately did not drop either.  Anyway, I noticed many camera phone snapshots show the disc as fully and uniformly illuminated.

    Is that a function of the lens refraction or reflection in the lenses that is canceled shooting through the filters?

       
    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