Skip to content

Sky chart

The Sky Chart at /tools/sky-chart is an interactive map of the night sky — a visualization surface for finding objects, checking visibility, and planning observations.

What it does

  • Render the celestial sphere with bright-star catalog overlays and visible NORAD satellite propagation.
  • Switch coordinate frames between equatorial, galactic, and horizontal.
  • Play back time forward and backward to see how the sky changes through a night or over longer baselines.
  • Identify what's visible from a given site at a given time.

When to use it

The sky chart is best as a standalone exploration tool — answer "what's overhead now," "where's that satellite going," or "what does the bright-star field around RA/Dec look like tonight."

For pre-observation target picking it's a complement, not a prerequisite. The observation editor's target step has its own picker (featured / search / custom coordinates) and is not wired to consume coordinates from the sky chart — you can browse in the chart for inspiration, then enter the target into the editor through the appropriate picker mode.

Where it lives in the app

In the React port, the sky chart is at apps/website-react/app/routes/tools/sky-chart.tsx (with an equivalent in the Angular shipping site). The rendering component lives in the in-tree packages/ts/sky-chart package so the same chart can be embedded in other surfaces — the editor's target step uses the same component for inline previews of featured targets.