Aurora & dark sky planner
For landscape and astro photographers
iPhone & Android
Most aurora apps hand you a Kp number and leave the hard part to you. Kp 5 is a great night in Minnesota and nothing at all in Texas — the number means nothing until you know what your own latitude needs.
Firstdark works out that threshold from where you are standing, checks it against the forecast, the moon and the cloud across your actual dark hours, and answers in a sentence.
What it does
The auroral oval sits at a geomagnetic latitude, not a geographic one — which is why Minnesota outperforms the same line of latitude in Europe. Firstdark computes your threshold from your coordinates, every time, and never reads it off a table.
Everglades: no aurora at any Kp. Fairbanks: you are inside the oval.
Cloud runs out at sixteen days and Kp at three. Past that, other apps quietly show you a number anyway. Firstdark says the sky is unknown rather than clear, marks a 27-day recurrence estimate as the guess it is, and never counts one as a forecast.
Not a filter over a white app. The entire palette swaps, and no white or green pixel survives it — so you can check the hour bars at 2am without spending twenty minutes getting your night vision back.
Sun, moon, twilight and the galactic centre are computed on the device and need no network at all. Cloud and space weather are cached with their age shown honestly — “Kp forecast from four hours ago”, not a blank screen in a dark car park.
Every lunar and solar eclipse to 2050, from NASA’s catalogues. For a solar eclipse it computes what you would see from where you are standing — magnitude, obscuration, contact times — rather than naming the countries the path crosses.
Checked against NASA’s published circumstances for all 66 eclipses.
The screens answer one question at arm’s length in the cold. The report is the other half: twenty-eight nights, every ranked subject with its reasoning, and where each number came from — as a PDF to save, send or take with you on paper.
The oval boundary is a rule of thumb, and no ephemeris can check it. After an alert, Firstdark asks whether you actually saw anything. A month of clear nights narrows the threshold to your own horizon, your own light dome, your own hills.
The four screens
One question, one answer, and the reasoning under it in a sentence you can read at arm’s length.
Your threshold, not a national one — and the solar wind reading that says whether the next hour is worth waiting out.
Four weeks ahead, narrowed to the nights that are actually worth it, with the eclipses that fall in range.
What is up, where to point, and where the light falls — ranked over the next eight weeks.
Checked against
| Quantity | Typical error | Worst case |
|---|---|---|
| Sunset | 0.5 min | 1.4 min |
| Civil twilight | 0.5 min | 1.3 min |
| Moonrise | 3.9 min | 12 min |
| Moon illumination | 0.7 pt | 1 pt |
| Solar eclipse duration | 0.2 s | 2 s |
Price
Free
$19.99 at launch, then $24.99 · paid once, not monthly
