weewx-skyfield

Using the Sky panels in your own skin

Home · Installation · Almanac tags · The Sky page · Translating (i18n) · GitHub project

---

Every panel on The Sky page is rendered by $sky_page — a standard WeeWX search-list extension, user.wxskyfield_sky, installed along with this extension — and can be dropped into any skin’s Cheetah template. Three things to arrange — four if your skin is not in English:

1. Add the search list to your skin’s skin.conf (if the skin already sets search_list_extensions, append user.wxskyfield_sky.SkyfieldSky to that list):

   [CheetahGenerator]
       search_list_extensions = user.wxskyfield_sky.SkyfieldSky
   

2. Have the Skyfield almanac registered — this extension installed, with enable = true (the default) in the Skyfield section of weewx.conf. The panels compute everything from the same public $almanac tags available to any template; the dome’s stars additionally come from the registered almanac’s star catalog.

3. Bring the CSS along. The colors of every mark are baked into the markup, but text styling and block layout come from CSS classes in the bundled skin’s stylesheet, skins/Skyfield/sky.css — mono, cardinal, gridlab and friends for the SVG labels; count, the chip family and the table rules for the HTML blocks. Copy the rules you need (or the whole file) into your skin’s stylesheet. If you copied individual rules, re-check on each upgrade: a release that adds marks to a panel can add a class (1.10 added moonlab, the sun-path moon-time labels), and text with no rule renders at the 16px SVG default in the wrong color — changes.txt calls out new classes.

4. Non-English skins only: bring the translations along the same way. The panels read [Texts] and [Almanac] from your report, not from the bundled skin, so without this step they render in English. The copy/merge recipe is on the translation page: Copying the dictionary into an embedding skin.

The bundled template, skins/Skyfield/index.html.tmpl, shows every panel in use and is the reference for the wrapper markup mentioned below. A failing panel never takes down report generation: the error is logged and that one panel renders blank. Body evaluations are memoized, so several panels on one page do not repeat the expensive rise/set searches.

Every render method takes an optional palette argument choosing the colors baked into the markup: 'night' (the default, used in the screenshots below) or 'light', a paper-atlas plate for light-themed pages: $sky_page.analemma_svg($almanac, palette='light'). As of 1.5 both plates draw the bodies in the traditional astronomy colors — yellow sun, silver moon, gray Mercury, pearly Venus, blue Earth, red Mars and so on — with pale bodies carrying a thin ring on the light plate so they hold their edge on paper; the pre-1.5 colors remain available as palette='classic-night' and 'classic-light'.

The sky dome — dome_svg

$sky_page.dome_svg($almanac)

Everything above the horizon right now, in sky-chart orientation — north at the top, east at the left, as if lying on your back looking up: the sun, the moon drawn at its true phase, the planets, and the bright IAU-named stars sized by magnitude, with hover coordinates on every mark. When the sun is up the stars are shown dimmed, standing where they are behind the daylight (sun_is_up, below, lets a caption react). dome_svg additionally takes label_scale (default 1.0), which grows every label by that factor with the collision layout following along — useful when a skin displays the chart scaled down, such as a fixed-canvas smartphone page: $sky_page.dome_svg($almanac, palette='light', label_scale=2.2).

Rise & set ribbons — ribbons_svg

$sky_page.ribbons_svg($almanac)

Today’s above-horizon span for the sun, moon and planets, over background bands of tonight’s civil, nautical and astronomical twilight (the USNO geometric definitions). The ivory tick on each bar is the transit; the vertical brass line is now, and the rise → set times are listed at the right.

The sun’s path — sunpath_svg

$sky_page.sunpath_svg($almanac)

Today’s sun, midnight to midnight, as altitude against azimuth — a dot every hour, labels every third. The dashed curve is the moon’s path, with the moon drawn at its true phase when above the plot floor; the bands below the horizon line are civil, nautical and astronomical twilight depth. Moonrise, moonset and the transit are ticked and labeled on the moon’s curve with times in the skin’s format, and the curve’s two ends — the moon’s positions at 00:00 and 24:00 — get dots labeled 00 and 24 when they clear the plot floor. The curve is open between those ends because a lunar day runs about 50 minutes longer than a calendar day, so a day’s track never quite closes; near full moon, when the moon transits around midnight, the break sits right at the top of its arc (the endpoint dots’ tooltips say so). The azimuth axis is the fixed full compass, north to north, so the arc’s seasonal swing between the solstices reads at a glance — and a circumpolar arctic sun needs no special casing.

The orrery — orrery_svg

$sky_page.orrery_svg($almanac)

Today’s heliocentric longitudes, viewed from above the north ecliptic pole; orbit spacing is logarithmic so Mercury through Neptune fit one plate. The dashed ray marks 0° — the direction of the vernal equinox.

The analemma — analemma_svg

$sky_page.analemma_svg($almanac)

The sun’s altitude and azimuth at local standard noon for every week of the year — the figure-eight sum of Earth’s tilt and its elliptical orbit — with this week’s point marked in brass. It evaluates the almanac 53 times (all cheap instantaneous positions).

The solar year — daylength_svg

$sky_page.daylength_svg($almanac)

Sunrise, sunset and solar noon (dashed) for every week of the year, over the same civil/nautical/astronomical twilight bands as the ribbons — with today’s brass line. Times are local clock time, so the daylight-saving steps in spring and fall are real and deliberate; the dashed solar-noon curve carries the equation of time (and the same DST steps). Polar day and polar night render correctly as all-day and no-day columns. This is the page’s most expensive panel — several hundred rise/set searches — but they are anchored to fixed weekly instants, so the result cache reuses them across report cycles and the full cost is paid only on the first render after startup.

The moon disc — moon_svg

$sky_page.moon_svg($almanac)

The moon at its true phase, waxing and waning on the correct limb. The optional size argument (default 76) sets the SVG’s intrinsic pixel size; with the bundled stylesheet’s svg{width:100%} rule the disc fills its container, so size the wrapping element.

The lunar month — lunation_svg

$sky_page.lunation_svg($almanac)

The current lunation, previous new moon to next, as a strip of thirty phase discs — the principal phases ticked and dated, today’s disc ringed in brass, and every disc carrying its date and illumination on hover. Waxing and waning fall on the correct limb for your hemisphere, matching the moon disc above.

Planet chips — chips_html

<div class="chips">
  $sky_page.chips_html($almanac)
</div>

A summary card per body: daylight (length, sun rise → set, civil dusk and astronomical dark), then each planet with its rise time or current position, the constellation it stands in, magnitude, distance and elongation — plus Jupiter’s central meridian longitudes and Saturn’s ring tilt. The chips wrapper provides the single-column layout.

Countdown chips — countdown_html

<div class="countdown">
  $sky_page.countdown_html($almanac)
</div>

Date and days-to-go chips for the next new moon, full moon, equinox and solstice, plus the next eclipse visible from the station (lunar or solar, whichever comes first, labeled with its locally seen type; its date carries the year, since the next visible eclipse can be years out). The countdown wrapper lays the chips out as a wrapping row.

The almanac table — table_html

<div class="tablewrap">
  $sky_page.table_html($almanac)
</div>

Rise, transit, set, time up, current altitude and azimuth, magnitude and distance for the sun, moon and planets. The tablewrap wrapper lets the table scroll sideways on narrow screens instead of breaking the page.

Helpers — header_sub and sun_is_up

$sky_page.header_sub($almanac) returns The Sky page’s one-line subtitle — station coordinates and the almanac time, e.g. 37.44° N · 122.14° W · Saturday, June 21 2025, 23:00 PDT. $sky_page.sun_is_up($almanac) returns a plain boolean for template logic; the bundled page uses it to switch the dome’s caption between day and night wording:

#if $sky_page.sun_is_up($almanac)
The sun is up, so the plate shows the stars where they stand behind the daylight.
#else
Dot size follows magnitude; the brighter the star, the larger the mark.
#end if

This site is open source. Improve this page.