Custom Star Map — the Night Sky for Any Moment
A custom star map shows exactly which stars stood over a particular place at a particular moment — a wedding, a birth, the night you met. This generator computes it from a real star catalog, free, entirely in your browser.
Make your custom star map
Free, in your browser, with no account and nothing to buy. The SVG, the 300 dpi PNG and the PDF (a real page of the size you pick, from 21 × 29.7 cm to 70 × 100 cm) are each the complete poster.
You pick the date, the time and the location (start typing a town name and pick it, or enter exact latitude and longitude). The chart then shows every star brighter than magnitude 5.0 that was above the horizon at that instant — typically 400–900 stars depending on season and latitude — plus the constellation figures connecting them, with your own title and caption beneath the sky disc.
Unlike a decorative print with a random sky on it, this chart is computed with standard positional astronomy — the same math planetarium software uses. Move the time by one hour and the whole sky rotates fifteen degrees, exactly as it did that night.
What you can customize
- Moment — date and time to the minute, any year from 1 to 3000.
- Place — a town or city picked from the list, or exact latitude/longitude; the place line can print decimal degrees, degrees-minutes-seconds, or no coordinates.
- Words — a title, a subtitle, and a dedication of up to three lines of 60 characters (on the two-sky poster too, centred under both skies), in Clean, Classic (Droid Serif) or Handwritten (Yellowtail) lettering.
- Look — six themes (navy night, ink on paper, sepia, blueprint, moss, noir) or your own three colours, checked for contrast before you print.
- Layers — star labels, constellation names in Latin or the poster’s language, the altitude/azimuth grid, the Milky Way, deep-sky objects.
Eight layouts from the same moment
The same date, time and town can be drawn eight ways, under Layout:
- One sky, the classic round chart with its caption. Its Shape box can cut that sky to a heart instead of a circle, keeping about 73% of it (heart-shaped star map).
- Two skies: two towns at one moment (long distance) or two dates (a life’s first and last nights).
- Family (3–4 skies): one disc for each child’s birth, or each of your nights, every one with its own date, time, town and a name of up to 30 characters above its place and date; the title on top and the dedication under all of them. Three sit in a row on a landscape size and two-over-one on a portrait print; four make a two-by-two grid, so on A4 each disc is about 37% of the sheet’s width (a one-sky poster’s disc is about 86%). Start a family poster, or see a family star map with one sky per child.
- Sky + Moon, the chart with the Moon drawn large above it (wedding night).
- Moon, the Moon alone, lit and tilted as it hung (the night you were born).
- Horizon view, the sky as you would have seen it standing there (what did the sky look like?).
- Observing chart, two black-on-white pages to take outside (constellation map).
- Moon calendar, every night of a year (printable Moon calendar).
What the chart draws
The chart holds the 1,630 stars brighter than magnitude 5.0 and the 89 constellation figures, and the Milky Way is drawn as a soft band. The Moon is drawn in its real phase, and left off when it was below your horizon. The five naked-eye planets, Mercury, Venus, Mars, Jupiter and Saturn, are drawn where they stood. The Sun is drawn too whenever it was up, and the caption says whether your moment was daylight, twilight or full dark: the stars are always drawn where they stood, even when daylight or twilight hid them. So is an eclipse, if your moment falls inside one. Uranus, Neptune and 133 deep-sky objects are one switch away: tick Deep-sky objects and the chart marks the Messier objects and southern showpieces and adds Uranus and Neptune (see them over London on a winter evening). Great comets since 1900 can be added (Hale-Bopp over London, 1997). Not drawn: faint comets and satellites, whose orbits this tool does not compute. Every position is carried to your date by precession. Not modelled: the stars’ own proper motion. A date before 15 October 1582 is read in the Julian calendar. It all runs in your browser, nothing is uploaded, and the downloads are complete and free. Accuracy, print sizes and privacy, answered in full.
Common questions
How is this different from a decorative star print?
A decorative print reuses one pretty sky. This one is recomputed for your minute and place: change the town from London to Sydney and half the constellations change, because Sydney sees the southern sky; change the time by four hours and the whole chart turns 60°. The caption under it says which moment it is, and the chart agrees.
Can I fix a mistake later?
Yes. Copy shareable link writes every choice (moment, place, words, theme, size, layers) into the address itself; open it later and the same poster comes back, ready to edit. Nothing is stored on a server, so keep the link.
Why is east on the left?
A star chart is read looking up. Facing the sky with north at the top, east is on your left, the mirror image of a map of the ground.