1. Planning Landmark Alignments (Moon, Sun & Milky Way)
To photograph the Moon, Sun, or Galactic Core directly behind a tower, mountain peak, or horizon monument, you can calculate sightlines using built-in presets (Eiffel Tower, Galata Tower, Mount Fuji), custom target landmark coordinates, or your own current GPS location.
- The 0.5° Angular Rule: Both the Sun and Moon have an apparent angular diameter of approximately 0.5° (30 arcminutes). Position yourself 1.5–10 km away with a telephoto lens (400–800mm) to make them look massive behind your subject.
- Elevation & Obstacles: The Alignment Finder factors in target top elevation and observer elevation to calculate true apparent altitude.
- Multi-Vantage Scanning & Up to 90-Day Search: Celestial azimuths drift significantly across seasons. Landmark presets automatically evaluate all curated shooting vantages around a monument across up to 90 days (~3 months) from your active planner date.
- Local Horizon Sightlines: When using your current GPS pin without a distant monument, the finder highlights iconic photographic moments—such as Full Moonrise during twilight.
- Field Margins & Tolerances: Choose from ±0.5° (Exact / Disk) up to ±2.0° (Wide Frame). In the field, ±1.0° to ±1.5° tolerance is recommended to account for positioning, natural terrain, and atmospheric refraction.
2. Golden Hour, Blue Hour & Twilight Phases
Light color temperature and quality are determined directly by solar elevation angle relative to the geometric horizon:
Golden Hour (+6° to -4°)
Warm, golden-red tones with long, soft directional shadows. Optimal for portraits, architectural silhouettes, and warm landscape side-lighting.
Blue Hour (-4° to -6°)
Rich cobalt-blue sky with ambient balance between fading daylight and warm city illuminations. Ideal for cityscapes and reflections.
Twilight Phases (-6° to -18°)
Civil & nautical twilight (-6° to -12°) reveals first stars while keeping the horizon visible for foreground blending; astronomical twilight (-12° to -18°) transitions to full night.
Astronomical Night (< -18°)
True optical darkness. The sky is completely dark, enabling high-contrast deep-sky astrophotography and Milky Way core capture.
3. Milky Way & Galactic Core Visibility
The brightest region of our galaxy — the Galactic Core — is only visible during specific seasonal and lunar conditions:
- Seasonality: In the Northern Hemisphere, Galactic Core season runs from late February through October. In the Southern Hemisphere, it arches higher overhead across winter months.
- The Dark Window: The Sun must be below -18° and the Moon either set or below ≤ 35% illumination.
- Prime Nights: Rated EXCELLENT on the Milky Way card when the dark window exceeds 2+ hours. Use the Month Calendar to pick low-illumination (0%–10%) nights around the New Moon.
4. Visualizers & Augmented Reality (AR Mode)
- Horizon 360 Panorama: Unwrapped cylindrical projection with symmetrical cardinal grid. Hover to inspect Azimuth and Altitude.
- Compass 2D Dial: Bird's-eye polar projection showing rise and set azimuth rays with 30° and 60° altitude rings.
- Augmented Reality (AR View): Live camera view with celestial paths and smart off-screen directional indicators.
- Compass Calibration & Celestial Alignment: Align to the real Sun or Moon with a single tap in the calibration drawer; aligning to either body automatically calibrates the entire sky (Sun, Moon & Milky Way). If the compass drifts, wave the phone in a figure-8 motion to reset the hardware magnetometer.
5. 100% Client-Side Ephemeris & Offline Privacy
All ephemeris calculations run locally inside your browser via Donald Cross's Astronomy Engine. Coordinates, custom landmarks, and saved shoot locations stay private on your device and are never sent to external servers.