weewx-skyfield 1.19 — the Sky page's dome draws the constellations

[John Kline]

Hi all,

weewx-skyfield 1.19 is out.  The Sky page's dome now draws the 88 IAU constellations: stick figures under the stars, each substantially-risen figure labeled with the constellation's name — in the report's language.  A setting figure is clipped at the horizon rim.  The figures are distilled from the Stellarium project's "modern" sky culture.

It all works with the bundled star catalog alone, is on by default, and upgrading from any 1.x is a drop-in — install over it, no config changes.  One option, constellation_lines = false, restores the plain dome.

Thanks to Jacques Terrettaz for suggesting the feature.

Screenshots are in the release notes:

https://github.com/chaunceygardiner/weewx-skyfield/releases/tag/v1.19

https://github.com/chaunceygardiner/weewx-skyfield

Release notes below.

John

weewx-skyfield 1.19

The Sky page's dome draws the constellations: the 88 IAU
constellations' stick figures, each substantially-risen figure labeled
with the constellation's name — translated, like everything else on the
page. Setting figures are clipped at the horizon rim,
planetarium-style. On by default and working with the bundled catalog
alone; drop-in upgrade from any 1.x — install over it, no config
changes. Suggested by Jacques Terrettaz.

What's new

• Constellation figures on the dome. The stick figures are
  distilled from the Stellarium project's
  "modern" sky culture (data CC BY-SA 4.0) and drawn under the stars,
  faint by day like the stars themselves. A setting figure is clipped
  where it crosses the horizon rim — the planetarium and printed
  all-sky-chart convention — instead of losing limbs star by star as
  its stars set. The whole layer is computed in one vectorized
  Skyfield observe and costs a few milliseconds per render.

  
  

  The solstice-night dome at the defaults:

  

  
  

  And with the full Hipparcos catalog installed, star_mag_limit = 5.0
  and star_label_mag = 2.5:

  

• Named, in your language. Each constellation at least half risen
  carries its name at the centroid of its visible stars, yielding to
  star and body labels when space is tight. The names read the same
  [Almanac] [[Constellations]] table the .constellation tag has
  used since 1.13, so the German page prints FUHRMANN under Auriga and
  the Danish page KUSKEN — no new translation work needed, all six
  bundled languages already carry all 88 names.

• One option. The figures are on by default;
  constellation_lines = false in the [[SkyfieldReport]] section of
  weewx.conf restores the plain dome.

• Stellarium credited in the footer. The page's footer adds
  "Constellation figures: Stellarium" — translated like the rest of the
  footer — exactly when the figures are drawn, alongside the ESA credit
  for the Hipparcos data; turn the figures off and the credit goes with
  them.

• Under the hood. The line figures ship as
  bin/user/wxskyfield_lines.dat; the bundled Hipparcos excerpt
  wxskyfield_stars.dat grows from 412 to 877 records to carry every
  line vertex (records byte-for-byte from the full catalog, as always).
  No full hip_main.dat is needed for the figures — and one adds
  nothing to them.

Requirements

• WeeWX 5.2 or later
• Python 3.9 or later
• Skyfield 1.47 or later, and NumPy

Installing/upgrading

Download weewx-skyfield.zip
and install with weectl, then restart WeeWX:

sudo -- bash -c ". /home/weewx/weewx-venv/bin/activate; weectl extension install weewx-skyfield.zip -y"

Upgrading from any 1.x is a drop-in: install over the old version; no
configuration changes are needed.