The Center button centers the selected object in the sky chart. Use this button if the selected object has moved off screen, and you want to re-center it in the field of view. The selected object will stay centered if you zoom in or out, or animate the sky chart using the Time Flow controls.
If you are using your device's gyroscope or compass/altimeter, then tapping the Center button will not center the selected object directly. Instead, an arrow appears, leading you toward the selected object. Move your phone in the direction of the arrow to center the object in the field of view. When the object is centered, the arrow disappears, and your phone will be pointing toward the object's position in the sky.
The Settings > Appearance & Behavior > Chart Animations switch provides animated panning to objects that you select and center in the sky chart. If turned off, the chart jumps instantly to objects when you center them. Please Note: this feature is only available in SkySafari Plus and Pro.