Skyfield

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

* 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``.

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

* An attempt at overly clever scripting resulted in a Skyfield 1.43
release without a ``setup.py`` in its ``.tar.gz``; within an hour, a
Python 2.7 user had reported that Skyfield could no longer install.
This release is identical to 1.43 but (hopefully) installs correctly
for everyone!

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

* Fixed :func:`~skyfield.magnitudelib.planetary_magnitude()` so it works
for Saturn even when the time is an array rather than a single time;
also, improved its calculation slightly with respect to Uranus.
`739 <https://github.com/skyfielders/python-skyfield/issues/739>`_

* Improved :func:`~skyfield.data.mpc.load_comets_dataframe()` so that
parsing ``CometEls.txt`` with the most recent version of Pandas
doesn’t stumble over the commas in the final field of (for example)
Halley’s Comet and give the error ``ParserError: Error tokenizing
data. C error: Expected 12 fields…saw 13``.
`707 <https://github.com/skyfielders/python-skyfield/issues/707>`_

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

* Added two new position methods
:meth:`~skyfield.positionlib.ICRF.phase_angle()`
and
:meth:`~skyfield.positionlib.ICRF.fraction_illuminated()`
that, given an illuminator (usually the Sun) as their argument,
compute whether the observer is looking at the bright side or the dark
side of the target body.
They replace a pair of old functions in the almanac module.

* The almanac routine :func:`~skyfield.almanac.moon_nodes()` would
sometimes skip nodes that were closer together than 14.0 days. It has
been tightened down and should now detect all lunar nodes.
`662 <https://github.com/skyfielders/python-skyfield/issues/662>`_

* Time objects now feature a :meth:`~skyfield.timelib.Time.to_astropy`
method.

* The position method :meth:`~skyfield.positionlib.ICRF.to_skycoord` now
sets the ``frame`` attribute of the sky coordinate it returns, and for
now only supports barycentric and geocentric positions.
`577 <https://github.com/skyfielders/python-skyfield/issues/577>`_