Free & open source · No account · Desktop and mobile
A real preview of your field of view. Before the first exposure.
12,000+deep-sky objects to explore
Your field of viewsingle frames and mosaics
Ready for the fieldoptional offline imagery
FROM “WHAT’S UP?” TO “THAT’S THE ONE.”
Plan with the sky in front of you.
Built for visual discovery, especially when your telescope can only see a small part of the sky.
01 / FIND YOUR NEXT TARGET
A whole sky of possibilities.
Pan around a 360° planetarium for your location and planning time. Search for a city or use your current location to set coordinates and timezone together. The planning clock and visibility charts follow local time at your observing site, including daylight-saving changes. The background shifts from black at night through twilight blues to light blue by day, while keeping stars and targets visible. Discover nebulae, galaxies and clusters as labelled dots, outlines or photographic thumbnails. Show all constellation lines, focus on your part of the sky, or hide them.
See a true angular field of view over the survey. Pan the object within your frame and compare Alt-Az and EQ orientation. Choose DWARF, Seestar and Vespera presets, or full-frame DSLR lenses from 24 to 400 mm. You can edit the field of view for your own setup.
Use Find for search results directly below the search box, Info for your selected object, and Filters to select multiple object types and filter by altitude, apparent size, magnitude, surface brightness and frame fill. Pause any filter—or all of them—without losing your settings.
Draw a polygon around your accessible sky, then use Edit points to drag individual corners. Save changes, cancel, or redraw from scratch. The patch filter stays active even when catalogue filters are paused. While drawing, hold Space and drag to pan on desktop, or use two fingers to pan and pinch on mobile. Single taps add corners; scrolling zooms without leaving drawing mode. It stays fixed to the local horizon while objects move through it. Switch the patch filter on or off whenever you need.
Compare physical disc sizes with your telescope frame at your chosen time and location. These are scale footprints, not simulated surface photographs. Always fit the correct solar filter before pointing at the Sun.
Find alternate catalogue names and read an offline object introduction, open Wikipedia without leaving the planner, or jump to SIMBAD for scientific data and ESA/Hubble for image searches and captions.
Move the planning time through daylight, civil, nautical and astronomical twilight. The sky colour follows the Sun while stars and objects stay visible for planning.
See its altitude through the observing day, with start/end times above the horizon and inside your saved sky patch. Preview another time without leaving the planner. Works offline.
Choose a city, use your current location, or enter coordinates. Coordinates and timezone update together, so midnight in Spain means midnight in Spain—even on a device set to another timezone. Current-location timezone detection also works offline.
The same app works on your laptop and phone. A bottom drawer keeps mobile controls within reach; drag to pan and pinch to zoom. Hide the time panel for more sky, then bring it back with Show time.
Save it before you leave, then explore your sky without a connection. Offline use works on desktop too—not just mobile.
Room for the sky. Controls at hand.Install is easy to find.
Online once. Offline when it matters.
1
Install first on iPhone / iPad
Add to Home Screen, then open the new icon while online before downloading. Safari downloads are not copied into the installed app. The core saves automatically: about 9.6 MB for the planetarium, bundled bright stars, catalogue and framing tools. In App status, wait for “Core ready offline”.
2
Choose your imagery
Keep the core alone, or add the all-sky survey overview. Our test download was 42.8 MB, with an 80 MB cap. Cancel, resume or remove it anytime.
3
Install—or bookmark
Use the top-bar status button: Install in your browser, App when installed, or Offline without a connection. It opens downloads, offline readiness, release notes and update controls. Installed apps do not show the installation prompt. Use the browser install button where supported. On iPhone/iPad, use Safari → Share → Add to Home Screen. Chrome/Edge on desktop and Android offer app installation; recent Mac Safari offers File → Add to Dock.
Installation is optional: offline saving also works in a supported browser. Fine survey detail, object preview photos, Wikipedia and external links still need internet. Browser storage can be cleared; check readiness and try an offline reload before your trip.
Keep your planner up to date.
New releases download when you open the app online. Choose Update now when you’re ready, or Later to keep planning. Saved preferences and survey downloads stay with you.
Open App status to check for updates and see your installed version. Read what’s new →
A FEW THINGS YOU MIGHT WONDER
Before you head outside.
Is Sky Patch free?
Yes. The app is free to use, with no account, subscription or advertising. The code is public under AGPL-3.0, with separate credits and licences for its data and dependencies.
Do I need a DWARF Mini?
No. Choose presets for DWARF, Seestar and Vespera telescopes or a full-frame DSLR with lenses from 24 to 400 mm. You can also edit the field width and height directly. The preset is 2.14° × 1.20° at 1920 × 1080; check your own equipment’s actual field of view.
Will my photographs look like the survey?
The preview shows angular scale and framing, not a prediction of image quality. Your telescope, exposure time, processing, seeing and sky brightness determine the detail you capture. The offline survey overview is intentionally lower resolution.
Can my laptop use it offline too?
Yes. Open the planner online and let the core finish saving. You can then use the catalogue, star map, planning time, filters and framing offline on desktop or mobile. Installing it provides an app icon and separate window where supported, but is not required for offline caching.
Does it control my telescope?
No. Sky Patch helps you choose and frame a target. Use your telescope’s own software to slew and take photographs. The app does not connect to or control your equipment.
How does the visible-sky patch work?
Click or tap corners around your accessible view. The polygon stays fixed in local altitude and azimuth. Filtering checks object centres, not whether the whole object or camera frame fits inside. One patch is saved per browser; redraw it if you change observing sites.
Where are my settings saved?
Location, equipment, filters and your sky patch are stored locally in your browser. They don’t sync between devices. Online imagery and reference requests go to the respective providers. There are no app accounts or analytics.
Actual app screenshot · enlarge ↗
