NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Celestial Tools V4.4.0 Beta 2
From: Stan K
Date: 2014 Jan 22, 15:34 -0500
From: Stan K
Date: 2014 Jan 22, 15:34 -0500
After running some more examples, I found that the 249 sight reduction in the original beta release of Celestial Tools V4.4.0 was flawed. The attached Beta 2 has 249 fixed (I hope) and a functional 229 (again, I hope).
There are a couple of things I noted while working on 229:
One of my books says that a mathematical interpolation for the corrections will not always match the interpolation tables in 229. Celestial Tools does the interpolation mathematically, and I found this to be true in a couple of cases. Both were in the value of d2corr, and both were off by 0.1'. My feeling is to leave it as is, with a note about it in the Help.
The DSD correction is only needed for Hc values above 60º, and only with certain combinations of latitude, declination, and LHA. The way it stands now, Celestial Tools will always calculate and display the DSD value and DSD correction, whether it is needed or not. (In most cases the DSD correction will be zero anyway.) To quote 229, "Although the effects of second differences may not be required, these effects can always be included in the interpolation whenever it is desired to obtain greater accuracy."
Considering the intention of Celestial Tools is to help students find errors in their work, rather than to do the work for the students, I am considering leaving things the way they are. If anyone can think of a compelling reason for me to make a change, please let me know.
Stan
There are a couple of things I noted while working on 229:
One of my books says that a mathematical interpolation for the corrections will not always match the interpolation tables in 229. Celestial Tools does the interpolation mathematically, and I found this to be true in a couple of cases. Both were in the value of d2corr, and both were off by 0.1'. My feeling is to leave it as is, with a note about it in the Help.
The DSD correction is only needed for Hc values above 60º, and only with certain combinations of latitude, declination, and LHA. The way it stands now, Celestial Tools will always calculate and display the DSD value and DSD correction, whether it is needed or not. (In most cases the DSD correction will be zero anyway.) To quote 229, "Although the effects of second differences may not be required, these effects can always be included in the interpolation whenever it is desired to obtain greater accuracy."
Considering the intention of Celestial Tools is to help students find errors in their work, rather than to do the work for the students, I am considering leaving things the way they are. If anyone can think of a compelling reason for me to make a change, please let me know.
Stan
