Measure your horizon
Hold the phone upright. Put the crosshair on the top edge of an obstruction and set a point. At hard edges (wall corner, roof line) set one point just left and one just right of the edge.
For the north reference, calibrate once on the sun or on a target with known coordinates.
On start the app asks for motion sensors, camera and location, one after another. Allow all three, otherwise you lose either the aiming image or the sun calibration.
← Back to the guideHorizon profile
Points
Measurement location
Measure at the planned telescope position, at objective height. The height is only stored with the data.
North calibration
The offset is applied to all stored points, retroactively as well. The raw sensor values are kept.
Switch to "Sun" mode and put the crosshair on the sun. Aim using the screen only, never look through a camera or any optics with your eye. Works best at a solar altitude between 10° and 60°.
Church spire, mast or summit: tap the coordinates in Google Maps, copy them and paste them here.
Trigger
The reading is the average of the last 0.5 s. The delay lets the phone settle after you tap.
For each point you set, a small camera snapshot is saved and shown in the profile as a photo strip next to the altitude line. Stays entirely on the device, never uploaded. Automatically switched off with very many points or low storage space, points already set are kept.
Export
ZIP containing landscape.ini and horizon.txt. Azimuth from north towards east, the way Stellarium expects it. Import: Stellarium, Sky and viewing options (F4), Landscape, plus symbol, pick the ZIP. Then set the location in Stellarium yourself.
JSON with points, 1° profile, location and calibration data. It also contains the raw values and, if enabled, the photo for each point, so the measurement can be reloaded later. With photos the file becomes noticeably larger.
Text file with azimuth and altitude per line for the custom horizon.
Continue working on a previously exported JSON file.