How to read the Sky Planner
The Sky Planner combines five data streams into a single dashboard. The Shoot Tonight score is a composite of weather conditions, moon darkness, and golden hour duration — a quick verdict on whether the night is worth the trip.
The day timeline shows every phase from astronomical twilight through civil twilight, golden hour, and full day — color-coded so you can see at a glance when to set up and when to pack down.
Milky Way visibility
The Galactic Center (Sagittarius A*) must be above the horizon andthe sky must be in astronomical darkness (sun below −18°) for productive Milky Way photography. The planner scans the full night window and reports the exact visibility window and peak altitude.
Planet positions
Planet data is computed locally using simplified VSOP87 orbital mechanics (Jean Meeus, Astronomical Algorithms, Ch 33). Accuracy is approximately ±1° — sufficient for planning compositions and identifying planets in the field without a telescope.
Solar and lunar data use NASA JPL DE441 ephemeris calculations via the Astrian engine, with sub-arcminute precision.