Milky Way Visibility

What it does

Forecasts which nights the Milky Way's core is above the horizon during astronomical dark while the Moon is not bright enough to wash it out.

What you need

A location, set with the location picker at the top. Without one, the screen asks you to set it in Settings. The calculation runs on the device, so no network connection is needed.

How to use it

1. Set your location.
2. Above the drag ruler, choose Hours or Days. Hours (the default) moves the time through the core's pass in 10-minute steps; Days changes the date. You can also pick a date with the date field or a day in the calendar. The button beside the date field reads Now in Hours mode and Today in Days mode, and returns you there. Use the month arrows on the calendar to browse other months.
3. Read the result card for that night.
4. Scroll to 30-Night Forecast and use the arrows to move through 30-night ranges.
5. Tap View on Map to open the Location Planner at your location and date.

Reading the results

• Result label: Clear Window, Partial Window, or Not Visible. Clear means the usable window lasts at least two hours. Partial means it is shorter than two hours.
• Dome: the core's pass across the sky that night, from Core rise to Core set, colored by what the sky is doing. The legend reads Sky not dark (with the time it gets dark), Clear window, and Moonlit, and a dot marks each change. Inside the dome, Shoot shows the window's start and end, its length, the Moon's illumination, and how high the core gets. When there is no usable time it reads No clear window. A pill between the ends counts down with "Window in" or "Ends in", or shows the time you moved the ruler to.
• Core never rises: if the core never gets above the horizon from your location, there is no dome and a short note says so.
• After midnight: on today, before midday at your location, the dome and result show last night until the core sets, since that is the pass still in the sky.
• Calendar: each day carries an eye icon for its state (clear, partial, or not visible).
• 30-Night Forecast: one row per night with the date, window, moon illumination, and the same eye icon.

Live Activity countdown

The Live Activity card counts down to the Milky Way window starting, then ending. Under Count down to, choose Start, End, or Both. If there is no window tonight at your location, the card says so. It is part of Pro and only on iPhone. Tap Start countdown to put it on your Lock Screen, and in the Dynamic Island on iPhones that have one. On the Free plan the button reads Start countdown (Pro) and opens the upgrade screen. Tap Stop countdown to end it. Changing a choice while it runs restarts it with the new choice. It only starts when you tap Start with the app open, replaces any other countdown that is running, and iOS ends it after about 8 hours. Settings, Notifications, Live Activities shows what is running and lets you stop it.

Tips

• On iPhone, a compass card under the location shows your live heading and tells you which way to turn to face the galactic core, for example "Turn left to face the galactic core". When you are pointed at it, the card's border lights up and the hint says it is straight ahead. When the core is down it says it is below the horizon. It shows on any date, always pointing at where the core is right now, and carries a small Now label to say so. If it shows Tap for live heading, tap it to start; if it shows Allow location in Settings, location access is off. It is not shown on web.
• Aim for nights marked Clear Window that also fall near a new moon.
• The calendar and the 30-night list move independently. Browsing one does not change the other.