https://bugs.kde.org/show_bug.cgi?id=309164

Jasem Mutlaq <[email protected]> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
            Version|                            |3.8.6
  Fixed/Implemented|                            |
                 In|                            |
             Status|REOPENED                    |RESOLVED
      Latest Commit|http://commits.kde.org/ksta |https://invent.kde.org/educ
                   |rs/cf2f4e250a54be94b613d2e8 |ation/kstars/-/commit/76298
                   |107da8377e00ff1e            |abd7901719b030dfb3c9ec90aac
                   |                            |c2b092e8

--- Comment #3 from Jasem Mutlaq <[email protected]> ---
Git commit 76298abd7901719b030dfb3c9ec90aacc2b092e8 by Jasem Mutlaq.
Committed on 06/11/2026 at 14:21.
Pushed by mutlaqja into branch 'master'.

Fix the epochs, duplicates and rounding errors of the star catalogs

KStars takes every catalog position as J2000.0 and applies proper motion
from J2000.0, but part of the bright star records still held their
J1991.25 Hipparcos positions: stars.dat was corrected in 2012, the binary
files KStars reads never were. Fast stars were drawn up to 1' off (Sirius
12", Arcturus 20", alpha Cen 32", 61 Cyg A 46", Groombridge 1830 62").

kstars/data/tools/fix-star-catalogs.py repairs the data; running it again
is a no-op:
- stars-dat: the 2012 conversion wrote Dec seconds of 59.05" and more as
  00.0" of the next minute (2005 rows, up to 1") and 12 RA seconds as 60.
- epoch: moves the 492 stale stars (655 records) of namedstars.dat and
  unnamedstars.dat to J2000.0 along their own proper motion, which keeps
  the trixel index and the record order starnames.dat relies on.
- dedupe: removes stars listed twice (Hipparcos and Tycho copies of one
  star, which overlapped once the epochs were fixed) and proper-motion-less
  "ghosts" of moving stars. Records with bit-identical astrometry are kept:
  they are the components of close doubles.
- xhip: fixes, from the Extended Hipparcos Compilation, records left at
  their Tycho-1 epoch (HD 39881, 161612, 148704, Algieba) and HD 101207,
  which had lost its proper motion.

Every removed star was checked against XHIP: each sits where XHIP has a
single star. Against XHIP, stars more than 1" off drop from 135 to 4 in
namedstars.dat and from 230 to 26 in unnamedstars.dat; the rest are
binaries with orbital motion and components of multiple systems.

The same tool fixed the downloadable Tycho-2 deepstars.dat, published as
version 1.2 through KNewStuff.

Tests/skyobjects/test_starcatalogs checks J2000.0 positions, the J1991.25
round trip, duplicates, ghosts and the stars.dat format, and the Tycho-2
catalog when KSTARS_TEST_DEEPSTARS points to it.
FIXED-IN: 3.8.6

Co-Authored-By: Claude Opus 5.5 <[email protected]>

M  +1    -0    Tests/README.md
M  +5    -0    Tests/skyobjects/CMakeLists.txt
A  +559  -0    Tests/skyobjects/test_starcatalogs.cpp     [License: GPL(v2.0+)]
M  +-    --    kstars/data/namedstars.dat
M  +2017 -2017 kstars/data/stars.dat
M  +11   -0    kstars/data/tools/README.tools
A  +584  -0    kstars/data/tools/fix-star-catalogs.py
M  +-    --    kstars/data/unnamedstars.dat

https://invent.kde.org/education/kstars/-/commit/76298abd7901719b030dfb3c9ec90aacc2b092e8

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