How to plan star trails
A rock beneath circling stars: the foreground stays put while the sky keeps turning. The preview shows how direction and recording duration change the picture.
01Choose the viewpoint and foreground
Set your camera position on the map and tap “3D” with the cube icon at the top. Aim the frame at your foreground. At northern latitudes, looking north gives you arcs around the north celestial pole.
02Set focal length and orientation
Pinch to choose a wide view. The rectangle icon on the right switches between portrait and landscape. Leave room around the centre of the arcs if you want circular shapes within the frame.
03Enable star trails
Tap the star with curved trails on the right. The duration appears alongside; change it with minus and plus. If the values have collapsed, the small arrow reveals them again. Celeris shows trails lasting from one minute to four hours.
The duration sits between minus and plus beside the star-trail icon. 04Set the end of the sequence
Trails end at the currently selected time. If your sequence starts at 9 pm and lasts two hours, set 11 pm and a two-hour trail duration. Exposures and the gaps between them both count towards the total duration.
The preview shows arcs for the chosen duration, ending at the selected time. 05Check light and frame edges
Compare durations and check both the start and end for twilight and moonlight. Save the plan. Choose individual exposure times and gaps on your camera or timer, and combine the images in your stacking software.
The trails are a geometric preview. Clouds, blown highlights, interruptions and the processing of your stack are not simulated.