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    Astron v2.1 release.
    From: Bill Ritchie
    Date: 2019 Mar 23, 07:06 -0700

    Astron V2.1 release.

    Following Beta testing, I am pleased to announce the release of Astron V2.1. This has been completely rewritten as a webpage and supercedes the previous spreadsheet V1.15. Whilst the Home Page for sight reduction remains much as before, the flexibility afforded by JavaScript has enabled the addition of graphical sight log/plotter and sight planner utilities.

    The lunars section has been extended with much supplementary information. It can be used to calculate time and position from a lunar distance and 2 altitude sights and also, in the reverse direction, to calculate the lunar distance and 2 altitudes for a known time and position. I have also added a rather empirical ‘quality index’ which varies with many factors, including the alignment of the Moon’s motion relative to the other body. I would be delighted to receive feedback on this from some of the regular lunar contributors to NavList.

    Astron V2.1 can be run from:-


    The extensive User Notes can be downloaded from:-


    A brief PowerPoint presentation can be downloaded from



    As the subject of Zenith Fixes is current, I have added the original problem as an example in User Notes Chapter 12. The Astron result is S19° 22.36’ E006° 37.57 which is in close agreement with Andres’ result of  S19° 22.3 E006° 37.6.


    Bill Ritchie.

    Now back home at 50N 003W.

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