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Open the app and hold your iPhone up toward the sky, as if you were taking a photo. StarGazer Terrestrial shows the stars, constellations, and planets in that direction and follows along as you move the phone. Pinch to zoom in or out. Tap anything for details, or tap Find to search for a specific object.

Tap Find, search for what you want, and tap it. A banner at the top tells you where it is (for example, "Low in the southeast, 12° above the horizon") and which way to move: "Turn right 40°", "Tilt up 15°". A yellow arrow at the edge of the screen points the way too. When the object reaches the middle of the screen, the banner turns green and your phone gives a short buzz. You can also tap any object on screen and choose Guide me there.

StarGazer Terrestrial highlights whatever is closest to the small crosshair in the center of the screen. It draws a ring and a large name, and brightens the constellation it belongs to. The readout at the top also names it, for example "Sirius · in Canis Major".

The gold dashed outlines are famous star patterns (asterisms): shapes that aren't official constellations but that most people know, like the Big Dipper, Little Dipper, Orion's Belt, the Summer and Winter Triangles, the Teapot, and the Seven Sisters (Pleiades). The smaller names give everyday names: what a constellation means ("Ursa Major", the Great Bear), and popular nicknames for stars and planets, like Polaris (North Star) or Mars (Red Planet). Both can be turned off in Settings. You can also search for them: try "Big Dipper" or "North Star" in Find.

Dot size shows brightness. Stars, planets, and satellites all use the same scale, so a bigger dot really is a brighter object in the sky. The Sun and Moon are drawn at their true size, which is the same for both, with a minimum so they stay easy to see.

That's on purpose. StarGazer Terrestrial lets you look "through" the Earth to see the stars, planets, and satellites that are currently below your horizon, under a see-through ground layer with an orange horizon line. The readout says "Looking through the Earth" when you're aimed below the horizon. To make the ground solid instead, turn off See through the ground in Settings.

StarGazer Terrestrial relies on your iPhone's compass, which can be thrown off by nearby metal, magnets, cars, or phone cases with magnetic clasps. Step away from metal objects and slowly move your phone in a figure-eight a few times to recalibrate it. iOS may also prompt you to calibrate automatically. Make sure location access is allowed so the sky matches where you are.

Tap Satellites in the toolbar. StarGazer Terrestrial downloads the latest orbit data for the space stations and about 100 of the brightest satellites; you can also add Starlink in Settings. Solid green dots are lit by the Sun and may be visible to your eye. Hollow dots are in Earth's shadow and can't be seen. The ISS is easiest to spot shortly after sunset or before sunrise.

In Motion mode (the default), the view follows where you point your phone. In Manual mode, you hold the phone however you like and drag with your finger to look around. That's handy for exploring the sky from the couch.

Tap Camera to show your iPhone camera's live view behind the sky. StarGazer Terrestrial draws the stars at the same field of view as the camera's lens, so constellation lines and labels sit on top of the real stars in the picture. Because the drawing is locked to the lens, pinch-to-zoom is turned off while the camera is on. The camera view is most useful at twilight or with bright objects like the Moon and planets; in full darkness a phone camera sees few stars, so the drawn sky does most of the work. If the drawing and the picture are slightly offset, recalibrate your compass (see above). The camera picture is never recorded or saved.

Night turns the whole display red, which protects the night vision your eyes build up in the dark.

No. Stars, constellations, planets, and the Moon are all calculated on your device and work fully offline, which is great for dark-sky sites. An internet connection is needed only to download satellite orbit data when you turn satellites on; it's then kept on your phone and refreshed about twice a day.

No. Your location is used only on your iPhone to work out which part of the sky is overhead. It's never sent to us or anyone else. See our Copyright & Privacy page for full details.

StarGazer Terrestrial is currently iPhone-only. It will run on an iPad in compatibility mode, but the layout is designed and tuned for iPhone screens.