What AstroNight does for you

Everything in AstroNight starts with the gear that you own. You can save one rig or several, and each one is made of a camera body, a lens or a telescope, a mount or a star tracker and any filters that you use. Most of it can be chosen from a searchable catalogue that comes with the app and fills in the technical details for you, and if your particular model is not in the list you can simply type it in yourself.

The app also looks at how elaborate a rig is. A phone on a small tripod and a guided refractor with a narrowband filter need very different advice, so the wording of every suggestion is adjusted to match, plain and encouraging for a simple setup and more technical for a complicated one. The catalogue is stored inside the app, so none of this needs a connection.

The plan for the evening is worked out from your own date and location. AstroNight calculates when the sun sets, when twilight ends and when the sky becomes truly dark, using the same solar equations that public astronomy calculators use, and it does this on the phone itself. In northern summers, when the sky never quite reaches full darkness, the app tells you exactly that instead of showing an hour that does not exist.

Beside the dark hours you see the brightness of the moon, an estimate of how dark your sky is on the Bortle scale, and the cloud cover and humidity at your location. From these the app suggests between one and three targets for the night together with sensible starting settings and a short sentence explaining why each one was chosen. On a washed out moonlit night the suggestions lean towards bright objects and narrowband imaging, and on a dark and moonless night they lean towards the Milky Way and the fainter galaxies. When the northern lights are likely at your latitude they appear in the plan as well.

A browsable catalogue of more than seventy targets sits alongside the plan for the evenings when you would rather choose for yourself, and it adjusts its settings to the equipment you saved.

After a night out you can record what you shot, how many frames you took, the settings you used and how the conditions were. A single tap on the plan fills most of this in for you, and you can still change anything by hand. If you add a photograph, AstroNight studies it right on your phone and looks for the things that most often go wrong, which are darker corners caused by vignetting, a colour cast that leans towards one channel, a brightness gradient from one side of the frame to the other, and a lack of sharpness.

The analysis is honest about what a single frame can tell. A star that is out of focus and a star that has trailed because the mount drifted both look soft, and when the app cannot tell which of the two you are seeing it says so plainly and suggests how to find out. Your photograph is analysed on the device and is not sent anywhere.

Every session you log is kept in a history that you can scroll through in order. When you have photographed the same target more than once, a comparison view lays those nights side by side, so that you can see how the Andromeda Galaxy from your first attempt differs from the one you took after learning to focus carefully, and what was different on the night when it went well.

The calendar gathers meteor showers, eclipses, comets and the days on which aurora look promising, so that you can plan a trip or simply keep an evening free. The northern lights forecast is checked once a day, and you can ask the app to check again when a geomagnetic storm is under way and you are watching closely. When the phone is offline the calendar shows the most recent information that it saved.