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Hoshi Stars星

The stars you can see without a telescope, with names, colours and distances; the 88 constellations with their lines and boundaries; the Messier objects; and seven map projections to draw them on.

Hoshi is the Japanese word 星 for a star. About the name

Contents

How-to

Embed a chart in an iframe

Put a sky chart on a page you cannot run script on, by the address of the embed page, and what each part of the address does.

日本語

For a page that cannot run script of its own (a blog, a wiki, a CMS), the demo site has embed.html: a page that draws the chart its address asks for and nothing else.

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Hoshi Stars in an iframe</title>
  </head>
  <body>
    <iframe
      src="https://johnmorrisdotca.github.io/hoshi-stars/embed.html?proj=stereographic&ra=84&dec=0&zoom=1.5&mag=5&layers=lines,names&c=Ori"
      title="A chart of the sky around Orion"
      width="480"
      height="360"
      loading="lazy"
      style="border: 0"
    ></iframe>
  </body>
</html>

The chart fills the frame and draws again when the frame is resized. It fetches nothing but its own files.

The reader can move it: drag to turn the sky, pinch or use Ctrl or Command and the wheel to zoom, press +, -, the arrow keys or 0 with the frame focused, or use the three buttons (zoom in, zoom out, back to the start). At the opening view the plain wheel scrolls the page behind the frame; zoomed in, it moves the sky. The page writes where it looks (ra, dec, zoom) back into its own address as the reader moves it. The zoom runs from 0.1 (the whole sky, small) to 500 (about 0.7 degree across a desk-wide frame, as far in as a catalogue of naked-eye stars has anything to show). Light and dark make no difference: the chart is always a night sky.

The address

PartMeans
projOne of stereographic, orthographic, gnomonic, equidistant, equirectangular, mollweide, hammer.
ra, dec, zoomWhere it looks, in degrees, and how far in (0.1 to 500). Left out, it looks at Orion (ra=84, dec=0) about 90 degrees wide, or 60 when the frame is under 600 pixels wide.
magThe faintest star, 2 to 6.
layersA comma list of milky (the Milky Way), lines, boundaries, names, deep (Messier) and grid, or none. Left out, it is milky,lines,names,grid.
langja for constellation names in Japanese.
cA constellation (Ori) to draw brighter, with its boundary.

The demo's "Put it in your page" panel writes this address for the chart you are looking at, with the iframe tag.

When not to

An iframe cannot be styled from outside and costs a request. If you can run script, draw the chart yourself; it is a few lines and one page less.

View sourceEdit on GitHubMade from the source of @johnmorrisdotca/hoshi-stars 0.7.0.