deps: update skyfield requirement from >=1.49 to >=1.54 in /addon/skyfield

[dependabot]

Updates the requirements on skyfield to permit the latest version.

Changelog

Sourced from skyfield's changelog.

v1.54 — 2026 January 18

• Skyfield’s internal table for the ∆T Earth orientation parameter has been updated, so observations extend to this month and predictions to January 2027. Compared to the previous version of Skyfield, this changes the Earth’s rotation angle by up to 0.2 arcseconds in 2025 and 1.1 arcseconds in 2026.

• The :meth:~skyfield.positionlib.Astrometric.apparent() method now accepts an optional deflectors= argument that lets callers control the list of bodies (by default the Sun, Jupiter, and Saturn) for which the deflection of light is computed. Callers can provide an empty list to turn deflection off.

• The two routines :func:~skyfield.almanac.find_risings() and :func:~skyfield.almanac.find_settings() now skip deflection when computing the target’s apparent position, which increases their speed by around 30%. The routines aim for only millisecond precision, while deflection only makes a difference of microseconds.

• You can now subtract a NumPy array of floating point TT days from a Skyfield :class:~skyfield.timelib.Time object of the same length; previously, only a plain int or float was supported as the subtrahend.

• Bugfix: the apparent() method in previous Skyfield versions was using the wrong coordinates for Earth’s center when computing how Earth’s gravity deflects positions for topocentric observers. This has been fixed, and Skyfield’s test suite shows that agreement with the Naval Observatory’s high-precision NOVAS library has improved from 0.5 mas to 0.01 mas for topocentric positions. (Astrometric positions were already agreeing at the 0.01 mas level.)

v1.53 — 2025 April 7

• Fix: calling :meth:~skyfield.positionlib.Barycentric.observe() on a position generated by an ephemeris with multiple segments per target, like DE441, was raising an exception::

  File ".../skyfield/relativity.py", line 46, in add_deflection deflector = ephemeris[name] TypeError: 'NoneType' object is not subscriptable

  Users should no longer receive the exception. [#1063](https://github.com/brandon-rhodes/python-skyfield/issues/1063) <https://github.com/skyfielders/python-skyfield/issues/1063>_

v1.52 — 2025 March 18

... (truncated)

Commits

• dc71178 Declare version 1.54, with updated ∆T table
• 84ede63 Compute what difference new IERS tables make
• a692ae9 Stop rebuilding .npz files if arrays don’t change
• 43636c8 CHANGELOG: add new apparent() argument deflectors=
• d185fae Quick script to test for import loops
• 65a887e Docs: describe how to load >1 ephemeris file #145
• 4cf5f5d Docs: change CometEls.txt mention to actual link
• 52fd26c Don’t pre-build vector functions for eph segments
• 04cddb6 Allow segments to be removed from ephemeris object
• 4d73efb Fix broken Stellarium URL in example Python script
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot show <dependency name> ignore conditions will show all of the ignore conditions of the specified dependency
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

[dependabot]

Labels

The following labels could not be found: dependencies, python. Please create them before Dependabot can add them to a pull request.

Please fix the above issues or remove invalid values from dependabot.yml.