Skyslice

Skyslice tells you what's actually worth photographing tonight — from your balcony, not from an open field.

Most astronomy apps assume you have an unobstructed view of the entire sky. In reality, most people don't. A balcony usually gives you only a narrow slice between buildings, often with a roofline blocking the highest elevations. Skyslice is designed around that reality: simply define the portion of sky you can actually see, and it will show you only the celestial objects that pass through it.

Define your visible sky

Enter the compass sector visible from your balcony (measured clockwise from North), along with your minimum and maximum viewing altitude. If a roof or overhang blocks the upper sky, simply set the maximum altitude below 90°. An intuitive compass display lets you visualize your exact observing window at a glance.

Choose when you want to observe

Select from several observing modes:

• Darkness Only (Astronomical, Nautical, or Civil twilight)
• Sunset to Sunrise
• Custom Time Range

Whether you're planning a full astrophotography session or just checking the sky before bedtime, Skyslice identifies every catalog object that crosses your visible sector during your chosen timeframe, while clearly highlighting the hours of true darkness.

Know exactly where — and when — to look

For every visible target, Skyslice provides:

• Apparent magnitude
• Object type
• Angular size
• Best observation time (when it reaches its highest point within your window)
• Altitude and compass direction
• Full visibility interval
• A compact night timeline showing exactly when it's in view

Filter for your equipment and conditions

Sort your targets by magnitude, apparent size, visibility duration, object type, or name. Powerful filters help you narrow the list to objects that match your telescope, camera, and local sky quality.

Preview the target before setting up

Each object includes a real photograph from Wikipedia whenever one is available. If not, Skyslice automatically displays a live DSS2 colour sky survey image of the exact coordinates, giving you a realistic telescope-like preview of the field you'll be imaging.

Plan ahead

Change the observing date to prepare future sessions. The Moon and planets are fully integrated, with live positions and magnitudes, so you'll always know what's visible — and what might interfere with your deep-sky targets.

Built for the field, works offline

The astronomical calculations and object catalog are fully bundled into the app. No account is required, and no initial setup is needed. Only the reference images require an internet connection. Set your observing location manually or simply tap "Use My Location."

Stop hauling your equipment outside hoping something interesting happens to be visible. Skyslice turns your balcony's awkward little patch of sky into a carefully planned astrophotography target list.