Skyfield

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

* Fix: teach Skyfield the new format of the Naval Observatory ∆T data
file ``deltat.preds``, whose change in format caused Skyfield to start
throwing an exception for new users.
`236 <https://github.com/skyfielders/python-skyfield/issues/236>`_

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

* Added :func:`~skyfield.almanac.seasons` to the :doc:`almanac` module
that can be used to predict solstices and equinoxes.

* Fix: the ecliptic coordinate routines no longer raise ``ValueError:
too many values to unpack`` if they are passed a time array.
`207 <https://github.com/skyfielders/python-skyfield/issues/207>`_
`208 <https://github.com/skyfielders/python-skyfield/issues/208>`_

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

* There is now an :doc:`almanac` module that can compute the times of
sunrise, sunset, and the phases of the moon, based on the search
algorithms announced at my recent PyBay talk “An Import Loop and a
Fiery Reentry.”

* Two new methods :meth:`~skyfield.positionlib.ICRF.cirs_xyz()` and
:meth:`~skyfield.positionlib.ICRF.cirs_radec()` have been contributed
which provide support for rotating a position into the Celestial
Intermediate Reference System (CIRS).
`192 <https://github.com/skyfielders/python-skyfield/issues/192>`_

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

* Skyfield now supports loading the Hipparcos star catalog as a Pandas
dataframe, providing the user with convenient mechanisms for looking
up a single star by HIP number or filtering the entire catalog by
magnitude. See :doc:`stars` for details.

* Ecliptic coordinates can now be produced for epochs other than J2000
thanks to a new optional parameter specifying the desired epoch for
the ``ecliptic_latlon()`` method.

* A position that gives a position, velocity, and time can now be
converted into full osculating orbital elements through the routine
:func:`~skyfield.elementslib.osculating_elements_of()`.

* A couple of bugs in the ``load()`` routine have been fixed.
`193 <https://github.com/skyfielders/python-skyfield/issues/193>`_
`194 <https://github.com/skyfielders/python-skyfield/issues/194>`_

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

* Both of the loader methods :meth:`~skyfield.iokit.Loader.open()` and
``tle()`` now accept not just URLs but also plain local file paths;
they correctly re-download a remote file if “reload=True” is
specified; and they allow specifying a different local “filename=”
than the one at the end of the URL.

* Earth satellite objects no longer try to instantiate a timescale object
of their own, which often kicked off an unexpected download of the three
files needed to build a timescale.

* Satellite names are now correctly loaded from Space-Track TLE files.

* The ability to create times using Julian Dates is now better advertised,
thanks to dedicated timescale methods whose names end in ``…_jd()``.

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

* The :meth:`~skyfield.positionlib.Geocentric.subpoint()` method
now normalizes the longitude values it returns
into the range −180° to 180°
`182 <https://github.com/skyfielders/python-skyfield/issues/182>`_
and returns an actual elevation instead of zero.
`185 <https://github.com/skyfielders/python-skyfield/issues/185>`_

* Earth satellites now return a real velocity vector instead of zero.
`187 <https://github.com/skyfielders/python-skyfield/issues/187>`_

* Earth satellites now offer an
:meth:`~skyfield.sgp4lib.EarthSatellite.ITRF_position_velocity_error()`
method that returns raw ITRF coordinates for users interested in them.
`85 <https://github.com/skyfielders/python-skyfield/issues/85>`_