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Compass & AR Help
If you have an iOS or Android device with a compass, SkySafari can show you the sky in same the direction that you’re holding your phone. As you move the phone around, the view on the sky chart follows your motion. You can identify stars and planets by holding your phone up next to them, and you can find any object in the sky by following an arrow that points in its direction.
On iOS devices, SkySafari can show you an Augmented Reality (AR) view that blends the star chart with the real sky, captured from your device’s camera.
Please note: some devices, like the iPod Touch and Kindle Fire, have a gyroscope but no compass. The icon for Compass will switch to a Gyro instead.
You can activate the compass (or gyro) as follows:
Tilt your device upward.
Tap the Compass icon in the toolbar (Android) or on the upper right of the screen (iOS).
On a device with gyro but no compass, tap the Gyro button in the toolbar to activate the gyro.
Tap the Compass (or Gyro) button again, or touch any part of the sky chart, to turn the compass (or gyroscope) off. You can enable or disable the “tilt up to use” compass feature in the Settings > Appearance & Behavior screen. You can turn off “Tilt to Use Compass” if you find that you’re accidentally activating the compass too often, or if you prefer to activate it from the compass icon found on the upper right corner of the sky chart.
Please note: in SkySafari Plus and Pro, the compass and gyroscope cannot be used when you are orbiting another object in the solar system. You can only use the compass when you are viewing from Earth. See the Orbit button Help for more information.
Using the Compass
SkySafari uses the compass to center the sky chart on the direction you’re holding your phone. You can also use it to find objects in the sky. To do this, first turn on the compass. Then tap Search, and enter the name of the object you’re looking for. When the Object Info view appears, tap the Locate button at the bottom of view. An arrow appears, leading you toward your selected object. Follow the arrow with your phone to center the object on the screen. When the object is centered, the arrow disappears, and your phone will be pointing toward the object’s position in the sky.
In SkySafari Plus and Pro, the compass and altimeter will be turned off if you connect to a telescope, or lock on the telescope’s position in the sky chart. The sky chart cannot be centered on the telescope’s position, and centered on the coordinates reported by the compass, at the same time.
A note on accuracy: the solid-state compass built into most mobile devices is not very accurate, and easily affected by interference. It can easily be wrong by ten degrees or more. The compass may be useful for locating bright objects in a general part of the sky, but it’s certainly not accurate enough to point a telescope.
Using Augmented Reality
SkySafari can shows you an Augmented Reality (AR) view of the sky. AR blends the simulated sky chart with a real view of your surroundings, captured from your device’s camera. Currently, AR is only available on iOS devices, and requires iOS 10 or later.
To use AR in SkySafari, first activate the compass, as described above. A small AR icon appears below the compass icon on the upper right of the screen. Tap the AR icon to turn on your device’s camera. If this is the first time you’ve used AR, your device will ask for your permission to use the camera. To turn off AR mode, tap the AR icon again. When AR is active, the on-screen buttons will be hidden.
During daylight hours, point your device’s camera at an area of clear blue sky. SkySafari will fill that area with a star chart. At night, point your camera at a black sky area. SkySafari will attempt to draw the star chart only over the sky area, and not walls, buildings, trees, etc.
You can increase or decrease the amount of sky chart blending with the camera’s video image by swiping up or down. At maximum blending, the star chart is drawn everywhere above the horizon, not just in clear sky areas.
You may find that the simulated objects in the sky chart don’t quite line up correctly with the real objects shown by the camera. This is due to the inaccuracy inherent in your device’s digital compass. To fix this problem, swipe the chart left-to-right. This way, you can align objects drawn in the chart with their images shown by the camera. The Moon is a great object to align on. The planets and brightest stars should also be visible in the camera and can be used for AR alignment.
Using the Gyro
Unlike the compass/accelerometer, the gyroscope measures your device’s orientation relative to a known starting point. The gyro does not measure your device’s true orientation relative to north/south/east/west or up/down in the sky. So to find your way around the sky with the gyroscope, you’ll need to use a slightly different process.
First, locate a known reference object in the sky, like the Moon. Then search for the same object in SkySafari, and center it on the screen. With the object centered, hold your device toward the object in the sky. Then tap the gyro button (with a finger in your other hand!) to turn on the gyro. Now, as you move your device around, the gyroscope follows its orientation relative to the object you used as a starting point. As you move the device around, the sky chart on the screen follows to match the view in the sky behind it.
As with the compass, you can use the gyroscope to find an object in the sky. Start with a known object in the sky, then find and center the same known object in SkySafari’s sky chart, and turn on the gyroscope - just as described above. Then search for the unknown object you’re trying to find in SkySafari. When the Object Info view appears for that object, tap the Center button. SkySafari show an arrow that leads toward the object; follow the arrow with your phone to find the object in the sky.