For general help and a feature overview, see help.md.
To produce an accurate sky map, Sky Map needs three things: the direction your phone is facing, where you are on the planet, and the current time. If the map looks wrong, one of these is likely off.
The most common cause is the device’s compass providing Sky Map with an incorrect direction. This is a hardware issue — it has nothing to do with Sky Map itself. Sky Map can only work with the data the sensor provides.
Things to try:
See About phone compasses for a deeper explanation of how phone compasses work and why they can go wrong.
Sky Map must know where on Earth you are to draw the correct sky. Without this, Sky Map defaults to 0° latitude / 0° longitude — a point in the middle of the ocean — and the map will look completely wrong wherever you are.
A telltale symptom: if Polaris (the Pole Star) appears near the horizon instead of high in the northern sky, Sky Map almost certainly doesn’t know your location.
To fix:
See also: Google’s guide to app permissions
Sky Map uses your device’s clock and time zone to calculate where objects appear in the sky. Time errors are uncommon, but an incorrect time zone in particular can shift the entire sky by several hours.
Open the Diagnostics page and confirm that the time and time zone shown there are correct. If they are wrong, that is a device clock issue rather than a Sky Map problem — correct it in your device’s system settings.
Sky Map doesn’t calculate your orientation from scratch — it reads the data provided by your phone’s built-in magnetometer. If the phone reports that its sensor is uncalibrated, Sky Map displays an accuracy warning.
Calibration is a hardware-level process that helps the sensor account for “Hard Iron” and “Soft Iron” distortions caused by the components inside the phone itself.
The goal: to ensure the sensor sees a consistent “circle” of magnetic data as you rotate the phone through all orientations.
The reality: calibration makes the sensor internally consistent, but it does not guarantee that it is pointing to True North.
Even a perfectly calibrated sensor can suffer from magnetic bias. The Earth’s magnetic field is a relatively weak signal, easily disturbed by:
The figure-8 calibration gesture (see video) forces the sensor to sample the magnetic field from many angles, allowing the hardware to filter out internal noise. Move to a clear area away from metal objects and magnetic sources before performing it.
This is a physical property of mobile hardware. If the map remains slightly shifted, your environment is likely causing a magnetic bias that the software cannot fully correct.
--,--,--.No. Sky Map works fully offline. An internet connection is only needed to:
Yes! Join the beta testing program on Google Play to get the latest version before it goes public.
Open the Diagnostics page from the overflow menu and email us at skymapdevs@gmail.com with a screenshot. It contains your sensor status, location, and time info which helps us diagnose problems quickly.