Instead of using decimal hours/degrees rounded to 4 decimal places,
I went back to the original constel.c and modified it to represent
both RA and DEC in degrees, and to round all values to the nearest
quarter arcminute. This seems closer to the original intent of the
constellation boundaries.
I'm using the HYG star database v3 from:
https://github.com/astronexus/HYG-Database
I compare the star constellations it reports against
what I calculate from the star RA/DEC it lists.
When I try this against all stars in the database, I
find 25 disagreements about which constellation contains
the star. Another person found 3 disagreements. See:
https://github.com/astronexus/HYG-Database/issues/21
For now, I'm testing only the stars brighter than mag 4.890,
which eliminates all the disagreements, and still gets me
over 1000 test cases.
Also, now I'm verifying ephemeris file and star database
checksums whether or not they have just been downloaded.
The idea is to catch corruption or unexpected changes
each time I run the unit test.
This unit test only exercises 8 different points.
I want to add a more thorough unit test soon, before
moving on to implementing the constellation finder in
the other supported programming languages.
