Version 4.2.0

• Elwood himself has contributed a new option that lets you switch XEphem from giving your telescope J2000 coordinates to giving it equinox-of-date coordinates.
• Sky View: the mouse wheel now zooms the view in and out.
• Sky View: DSS image download has been fixed by upgrading to HTTPS, and the window should no longer awkwardly resize once the image arrives.
• Data » Download: added the URL of the Celestrak “visual.txt” file.
• Data » Download: replaced “ftp.lowell.edu” with modern HTTPS.
• Data » Field Stars: François Meyer added support for the ucac5 catalog.
• The precession formula has been updated to the one from the 2000 Astronomical Almanac.
• A couple of compilation problems on modern Mac machines have been fixed.
• XEphem now uses more modern SSL setup routines if the code detects it’s being compiled against OpenSSL ≥1.1.
• Closing the INDI window with your window manager’s “Close” button no longer crashes XEphem.
• All references to “celestrak.com” have been changed to their new hostname “celestrak.org”.
• A few other small fixes.

SSL support plus updates to planetary moons, Pluto, and ∆T

• Downloads of Minor Planet Center files and of Earth weather maps have both been fixed, thanks to new SSL support. Thank you, Lutz Mändle!
• The files for the moons of Mars, Jupiter, Saturn, and Uranus that expired at the end of 2020 have been updated through 2040. Thanks you, IMCCE!
• Updates from the Astronomical Almanac 2020:
  • Pluto’s long-term orbital elements.
  • The ∆T table now runs through 2018.

Updated World Magnetic Model; better compilation

• Updated to the 2020-2025 World Magnetic Model.
• Fixed Halifax time zone, which was an hour off.
• Stop trying to link against `-lXp`, which X Windows no longer offers.
• Tell Linux folks to compile against their native Motif libraries.
• Remove pre-compiled Linux `libXm.a`: incompatible with modern X Windows.
• First release from the GitHub repository.

Final release from clearskyinstitute.com

• Tweaked "versionmenu.c" to fix a compiler error.
• Final release from the www.clearskyinstitute.com website.

First release under MIT License

This release preserves the state of the source code when the author Elwood Downey posted it to the XEphem web site on the day he donated it to the community by offering it under the MIT License. Thank you, Elwood!