Constellate — Support

Constellate turns a date, a time and a place into a print-ready star map. This page is the whole support channel: there is no account system and no ticketing, because there is no server.

Getting in touch

Email gapfound.apps@gmail.com. Please say which iPhone and which version of iOS you are on, and what you expected to happen. If a poster looks wrong, include the date, time and place you entered — that is usually enough to reproduce it exactly.

Common questions

Is the sky actually accurate? Yes. Star positions are computed from the Yale Bright Star Catalog with precession, nutation, aberration and parallax applied for your exact moment and location, and the Moon and planets from the standard analytical theories. The result is checked against NASA's JPL Horizons and agrees to within a few arcseconds — far finer than a printed poster can show.

Does it need an internet connection? No. The star catalogue, the city list and the timezone database are all bundled in the app. Everything except the purchase works in aeroplane mode, permanently.

Does it use the right timezone for an old date? Yes. Constellate carries the historical timezone database, so a date in 1987 uses 1987's rules for that place, including whatever daylight saving was in force at the time. If a local time is ambiguous or never existed because the clocks moved, the app says so rather than guessing.

What do I get when I export? A vector PDF, or a PNG at 300 DPI. Both include bleed and safe margins, and the PDF has its fonts embedded, so a print shop can use the file as-is.

Which size should I choose? Seven formats are included, from an A5 card to A2. Larger sheets place the caption below the sky; the landscape sheet places it alongside. The export screen states the exact pixel dimensions before you commit.

My export took a while. A 300 DPI A2 sheet is around 25 million pixels and is drawn in bands to stay within memory. The progress bar is accurate; give it up to a minute on a larger sheet.

I paid on another device. Open the unlock screen and choose Restore purchase. It uses the Apple Account signed in on the phone. There is no login of ours to recover, so this is the only step.

Can I use a poster commercially? Yes. What you make is yours. The underlying catalogues are public-domain scientific data or permissively licensed, and the app's typefaces are licensed for embedding.

Which iPhones does it run on? iPhone 8 and newer, on iOS 16.4 or later. It is an iPhone app; it is not built for iPad.

Data and deletion

Constellate stores your saved designs on your device, encrypted. Deleting the app removes them, and there is nothing held anywhere else to delete. See the privacy policy for what the in-app purchase involves.