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t_moon bug?


Hello all you experts -- I need help.  I downloaded and installed tmoon_laz using the Online Package Manager.  I am running on Windows 10, ver 21H1; Lazarus 2.2.2; FPC 3.2.2; x86_64-win64-win32/win64.  I tried to run the DEMO project included with the package (NewMoonTool) and it complied and ran after I commented out the line "{$define use_html_help_handler}" under "{$ifdef fpc}" in file mtMain.pas.

During my exploration of how the program works, I noticed that for various dates and observer locations, the moon transit time is shown as "--".  As an example:  for location Longitude = W 76° 48' 33", Latitude = N 39° 14' 22", I get the following results for the Moon:

 Date   5/26/2022      5/27/2022      5/28/2022
 Rise       7:49 UTC       8:13 UTC       8:38 UTC
 Transit   14:17 UTC        --         15:43 UTC
 Set      2:50 UTC      21:52 UTC      22:54 UTC
It makes no sense to me why the program produces "--" for the transit time for 5/27.  Upon examining the code, I noticed that the calculation of the transit time produces 0 ("zero") as the DateTime value.  Is this a bug in the algorithm (I suspect not) or an artifact of "number rounding" when calculating transcendental functions?  Can anyone explain this and is there a workaround?

Try to contact the original author of this package, Andreas Hörstemeier, on his github site:


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