Celestial Navigation

ERRORS FOUND in H.Umland’s  java script calculation programs previously shown on this page.

His Almanac produces incorrect data for current dates and therefore his calculation programs should not be used. Many thanks go to Carl Smithson for drawing our attention to these errors. We checked out his work a long time ago on a few of our 1970’s sextant sites and found it reasonably accurate.  But a check on his data for 2014/15 shows errors.

Teacup Navigation

A newer program has been released by Rodger Farley of Teacup Navigation which has more bells and whistles, including crossing multiple sights and stars sights. Rodger and I worked through a half dozen of our old sextant sights from the 70s to compare results and his program works to a tee. Furthermore, it produces accurate results for 2014/15  Check it out. It is also free.

Disclaimer by Rodger Farley of Teacup Navigation: USER BEWARE!  The programmer does not guarantee or warrant the accuracy or use or results of any of the materials provided here. You, the user, are TOTALLY responsible for validating the results from from these free materials, and you the user are TOTALLY responsible for any result that may occur from either the proper use, or the improper use of these materials.

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Comments

Celestial Navigation — 5 Comments

  1. Jack,

    Umland has updated his programs and they no longer produce errors. What a mess- the guy can only be contacted by fax! Fax?! What’s that?!

    Carl

  2. Umland’s javascripts and tables are JUNK!!!! Particularly, the “Almanac” ones will produce results which are incorrect by a huge margin. He wrote them based on old java or whatever you call it.

    Compare any set of figures using his programs against the USNO-

    http://aa.usno.navy.mil/data/docs/celnavtable.php

    Worse is that you can’t contact the guy with email as he claims he’s received too much spam.

    Cap’n Jack replies:
    “Thanks for stating your opinion, although we find them a tad harsh considering the amount of work H.Umland put into his free almanac and nav program. We checked out his work a long time ago on a few of our 70’s sextant sites and found it reasonably accurate.
    There is a newer program available at http://www.teacupnavigation.net/ It has more bells and whistles. I have communicated with its author and together we checked out a half dozen old sextant sights, which worked to a tee.”

  3. Pingback: Celestial Navigation - java calculation programs - SailNet Community

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