Skyfield

--------------------

* A new :meth:`~skyfield.sgp4lib.EarthSatellite.from_omm()` Earth
Satellite constructor has been added to load satellite elements from
modern OMM data instead of from old TLE data. The Earth satellite
documentation now :ref:`describes two OMM formats
<satellite-element-formats>` and :ref:`shows how to load satellites
from each one <loading-satellite-elements>`. `763
<https://github.com/skyfielders/python-skyfield/issues/763>`_

* If you print an instance of the
:class:`~skyfield.planetarylib.PlanetaryConstants` class to the screen,
it will list all of the segments that it has loaded from binary kernels.
`952 <https://github.com/skyfielders/python-skyfield/issues/952>`_

* The Skyfield documentation is no longer installed alongside the Python
code, reducing the size of Skyfield by around 25%. Users who need
offline access to the documentation will now need to download it
separately.

-----------------------

* Times now support the ``<`` operator, so Python can sort them.

* For convenience, geoids like :data:`~skyfield.toposlib.wgs84` have a
new attribute :data:`~skyfield.toposlib.Geoid.polar_radius`.

* You can no longer subtract two positions unless they have the same
``.center``. Otherwise, a ``ValueError`` is raised. This check has
always been performed when you subtract vector functions, but it was
missing from the position subtraction routine.

* On days that the Sun fails to rise and set in the Arctic and
Antarctic, the new rising and setting routines now correctly set the
value ``False`` not only for sunrise but also for sunset.

-----------------------

* Added faster and more accurate rising and setting routines!
See `risings-and-settings` for documentation and examples of the new
:func:`~skyfield.almanac.find_risings()` and
:func:`~skyfield.almanac.find_settings()` and
:func:`~skyfield.almanac.find_transits()` functions.
`662 <https://github.com/skyfielders/python-skyfield/issues/662>`_

* Skyfield’s internal table for the ∆T Earth orientation parameter has
been updated, so that its predictions now extend to 2025-01-18.

* Constellation abbreviations are now consistent between the
:func:`~skyfield.api.load_constellation_map()` table and the
:func:`~skyfield.api.load_constellation_names()` list. Previously,
``CVn`` and ``TrA`` had been mis-capitalized in the list as ``Cvn``
and ``Tra``.
`906 <https://github.com/skyfielders/python-skyfield/issues/906>`_

--------------------

* The :func:`~skyfield.almanac.oppositions_conjunctions()` routine now
measures ecliptic longitude using the ecliptic of each specific date,
rather than always using the J2000 ecliptic, which should improve its
accuracy by several seconds.

* Skyfield’s internal table for the ∆T Earth orientation parameter has
been updated, so that its predictions now extend to 2024-04-13.

* Bugfix: Skyfield was giving values several kilometers off when
computing the elevation above ground level of a target that was
positioned directly above the Earth’s north or south pole.

* Bugfix: the :func:`~skyfield.positionlib.ICRF.is_behind_earth()`
method was incorrectly returning ``True`` if the Earth was on the line
that joins the two satellites, but over on the far side of the other
satellite where it wasn’t really in the way.

* Internals: the :meth:`~skyfield.positionlib.ICRF.altaz()` method now
lives on the main position class instead of in two specific
subclasses. If the user mistakenly tries to call ``.altaz()`` on an
instance of the :class:`~skyfield.positionlib.Astrometric` position
subclass — which previously lacked the method — then a friendly
exception is raised explaining their error.

-------------------------

* Bugfix: minor planets and comets in Skyfield 1.44 would raise an
exception if asked for a position in the half of their orbit where
they are inbound towards their perihelion.

-------------------------

* Skyfield’s internal table for the ∆T Earth orientation parameter has
been updated, so that instead of including measurements only through
December 2021 it now knows Earth orientation through September 2022.

* Distance and velocity objects can now be created by calling their unit
names as constructors, like ``d = Distance.km(5.0)`` and
``v = Velocity.km_per_s(0.343)``.

* Updated the URL from which the Hipparcos database ``hip_main.dat`` is
downloaded, following a change in the domain for the University of
Strasbourg from ``u-strasbg.fr`` to ``unistra.fr``.