Skyfield

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

* A new :func:`~skyfield.eclipselib.lunar_eclipses()` routine finds
lunar eclipses and determines their degree of totality.
`445 <https://github.com/skyfielders/python-skyfield/issues/445>`_

* The almanac module’s new :func:`~skyfield.almanac.meridian_transits()`
routine can find the moments at which a body transits the meridian and
antimeridian.
`460 <https://github.com/skyfielders/python-skyfield/issues/460>`_

* Fix: the :func:`~skyfield.searchlib.find_minima()` function was
ignoring its ``epsilon`` and ``num`` arguments and always using the
default values instead.
`475 <https://github.com/skyfielders/python-skyfield/pull/475>`_

* Fix: the ``.epoch`` attribute of Earth satellite objects that were
built using :meth:`~skyfield.sgp4lib.EarthSatellite.from_satrec()`
was, alas, a half-day off.
`466 <https://github.com/skyfielders/python-skyfield/issues/466>`_

* Fix: the ``Topos`` constructor arguments ``x`` and ``y``,
which never worked properly anyway,
have been deprecated and are now ignored.

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

* Skyfield now uses the International Earth Rotation Service (IERS) file
``finals2000A.all`` for updated ∆T and leap seconds. The USNO is no
longer updating the files ``deltat.data`` and ``deltat.preds`` that
previous versions of Skyfield used, and the ``cddis.nasa.gov`` server
from which they were fetched will discontinue anonymous FTP on 2020
October 31. See `downloading-timescale-files`.
`452 <https://github.com/skyfielders/python-skyfield/issues/452>`_
`464 <https://github.com/skyfielders/python-skyfield/issues/464>`_

* The comets dataframe built from the MPC file ``CometEls.txt`` now
includes the ``reference`` column, so users can tell which orbit is
most recent if there are several orbits for a single comet. (For
example, the file currently lists two C/2020 F3 (NEOWISE) orbits.)
The comet examples in the documentation now build a dataframe that
only includes the most recent orbit for each comet.
`463 <https://github.com/skyfielders/python-skyfield/issues/463>`_

* Two new methods :meth:`~skyfield.iokit.Loader.days_old()` and
:meth:`~skyfield.iokit.Loader.download()` make it simple to download a
fresh copy of a file if the copy on disk is older than you would like.

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

* The various ``strftime()`` Skyfield methods now support the ``%j``
day-of-year format code.

* Fix: the new Julian calendar support broke support for out-of-range
month numbers, wrapping them into the current year instead of letting
them overflow into subsequent years.
`461 <https://github.com/skyfielders/python-skyfield/issues/461>`_

* Fix: a stray debugging ``print()`` statement was stranded in ``t.dut1``.
`455 <https://github.com/skyfielders/python-skyfield/issues/455>`_

* The :class:`~skyfield.timelib.Time` object, if manually instantiated
without a Julian date fraction, now provides a fraction array with
dimensions that match the Julian date argument.
`458 <https://github.com/skyfielders/python-skyfield/issues/458>`_

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

* Fix: the new Julian calendar feature was raising an exception in the
calendar methods like :meth:`~skyfield.timelib.Time.tt_calendar()` if
the time object was in fact an array of times.
`450 <https://github.com/skyfielders/python-skyfield/issues/450>`_

* Fix: trying to iterate over a time object would raise an exception if
the time was created through :meth:`~skyfield.timelib.Timescale.ut1()`.

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

* **Broken URL:** Because the VizieR archive apparently decided to
uncompress their copy of the ``hip_main.dat.gz`` Hipparcos catalog
file, the old URL now returns a 404 error. As an emergency fix, this
version of Skyfield switches to their uncompressed ``hip_main.dat``.
Hopefully they don’t compress it again and break the new URL! A more
permanent solution is discussed at:
`454 <https://github.com/skyfielders/python-skyfield/issues/454>`_

* To unblock this release, removed a few deprecated pre-1.0 experiments
from April 2015 in ``skyfield.hipparcos`` and ``skyfield.named_stars``
that broke because the Hipparcos catalog is no longer compressed;
hopefully no one was using them.

* In a sweeping internal change, the :meth:`~skyfield.timelib.Timescale`
and :meth:`~skyfield.timelib.Time` objects now offer support for the
Julian calendar that’s used by historians for dates preceding the
adoption of the Gregorian calendar in 1582. See `choice of calendars`
if you want to turn on Julian dates in your application.
`450 <https://github.com/skyfielders/python-skyfield/issues/450>`_

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

* The printed appearance of both vectors and of vector functions like
Earth locations and Earth satellites have been rewritten to be more
informative and consistent.

* Added :func:`~skyfield.timelib.compute_calendar_date()` which lets the
caller choose the Julian calendar for ancient dates instead of always
using the proleptic Gregorian calendar. This should be particularly
useful for historians.

* Added :meth:`~skyfield.timelib.Timescale.J()` that builds a time array
from an array of floating point years.
`436 <https://github.com/skyfielders/python-skyfield/issues/436>`_

* Added four new ``strftime`` methods for the non-UTC timescales
`(443). <https://github.com/skyfielders/python-skyfield/issues/443>`_
All four of them support ``%f`` for microseconds,
and provide a reasonable default format string
for callers who don’t wish to concoct their own:

* :meth:`~skyfield.timelib.Time.tai_strftime()`
* :meth:`~skyfield.timelib.Time.tt_strftime()`
* :meth:`~skyfield.timelib.Time.tdb_strftime()`
* :meth:`~skyfield.timelib.Time.ut1_strftime()`

* Thanks to several fixes, comets and asteroids with parabolic and
hyperbolic orbits should now raise fewer errors.

* The prototype :func:`~skyfield.magnitudelib.planetary_magnitude()` can
now return magnitudes for Uranus without raising an exception. The
routine does not yet take into account whether the observer is facing
the equator or poles of Uranus, so the magnitude predicted for the
planet will only be accurate to within about 0.1 magnitudes.