How to make a star map
What a star map actually is
A star map is the night sky of one moment, drawn flat: the stars and planets in the positions they truly held for a given date, time and place. Making one is really two jobs — computing those positions, and drawing them. Skymemento does both: the positions come from NASA JPL ephemeris data, and the drawing is rendered at print resolution.
The four steps
1. Pick the moment. Start with the date that matters — a birthday, a wedding day, the night a couple met, a date that remembers someone. Moments from 1900 through 2052 (UTC) are supported. Your selected local time is converted to UTC to check this range.
2. Choose the time and place. These matter as much as the date. The place decides the angle you saw the sky from, and the local time zone is applied automatically, so search the city, hospital, venue or address where the moment happened. Both a date and a local time are required for the preview and checkout. The editor cannot work out an unknown event time for you. If the time is unknown, choose an estimate deliberately; the common question below explains what that means for your map.
3. Preview it free. You'll see the sky immediately, with no account and no payment. The preview is watermarked; the file you buy isn't. Adjust the date, time or place until the sky is the one you want.
4. Download your map. Keep the digital files after payment:
Digital download — $5 CAD. A high-resolution PNG plus a scalable SVG. Digital file only; no physical item is shipped. If you plan to print it, check the format and size with your print shop, and keep the map's proportions.
Framed prints are coming soon — the tier is not on sale yet; the digital download is available now.
Make your star map — free preview
Printing your digital star map
Your PNG is 4096 × 5120 pixels, in a 4:5 portrait shape. Use the downloaded original, not a screenshot of the watermarked preview. Set your intended physical size in the printer or print shop settings. The unchanged PNG provides:
- 8 × 10 inches — 512 PPI
- 12 × 15 inches — 341.33 PPI
- 16 × 20 inches — 256 PPI
- 24 × 30 inches — 170.67 PPI
These figures are pixels per inch (PPI), not printer dots (DPI), and are not a print-quality guarantee. At 16 × 20 inches the PNG is 256 PPI, not native 300 PPI. Confirm the print service's requirements before ordering. Changing a PNG's resolution label does not add original image detail.
Keep the proportions locked and the entire map and caption visible. Avoid Fill or automatic cropping. A4, A3, US Letter and 5 × 7-inch paper have different proportions: fit the full map inside the page with margins rather than stretching or trimming it. Check the entire caption in the final print preview, including any borderless-printing trim.
For a larger print, ask whether the shop accepts the supplied SVG and can preserve its fonts and layout at your chosen size. Not every print service accepts SVG; check its proof before paying. PNG and SVG are supplied; a PDF is not included. Printing, paper and a frame cost extra and are not included in the digital purchase. Screen and printed colours can differ.
What makes it accurate
The honest test of a star map is whether it matches the real sky. We check our positions against documented astronomical events. Our reference test reproduces the Great Conjunction of 21 December 2020, when Jupiter and Saturn passed 6.1 arcminutes apart — their closest approach since 1623. If the map reproduces a known event that closely, it's reproducing your night too.
Every map is generated in Canada. Made in Canada. Star positions from NASA JPL ephemerides.
Common questions
Do I need to know the exact minute? You need to select a local time, but it can be an estimate when the original time is unknown. The map shows the sky at the time you enter. An estimated time is a keepsake choice, not a verified record of the original moment. Check your selected date, local time and place before paying.
Can I order it for someone else? Yes — pick their moment, add a short message (name, date, a few words), and download the PNG and SVG files. The star map gift page covers the gift angle.
Which occasion should I start from? Whichever fits: birth, wedding, anniversary, memorial, or the Canadian shop page, custom star map Canada.
Ordering
Every map is made to order and personalised, so all sales are final — please check your date, time and place carefully before you pay, and use the free preview to see the map first. See the refund policy.