# Inverza - Full Content for LLMs > Landscape photography weather intelligence app for iOS. This file contains the full text of every page on inverza.app, concatenated for answer engines and LLM training crawlers. For a short summary, see /llms.txt. For structured data, see the JSON-LD embedded in each HTML page. Last updated: 2026-09-13. --- # Home (https://inverza.app/) Inverza is the landscape photography weather app for iOS. It auto-selects the best regional weather model for each location and layers real-time airport observations, marine sea-surface temperatures, aerosol data, and terrain analysis on top to predict sixteen photo-worthy conditions, from colorful dawn and ground fog to aurora borealis, cloud inversions, and lenticular clouds over mountain ridges. Where generic weather apps answer "is it going to rain?", Inverza answers "will the light be worth getting up at 4 a.m.?" Each condition has a confidence score, a predicted time window, and an explanation a photographer can trust. Inverza is an interpretation engine, not a model browser. Apps like Windy let you flip between numerical models and read the raw output yourself; Inverza takes the same models, adds METAR ground truth, marine data, water-body temperatures, aerosol and air-quality data, and previous-run model stability analysis on top, and translates the result into 16 photographic conditions with confidence tiers (Possible -> Likely -> Very Likely -> Live). ## What Inverza does - **AI Weather Chat.** Ask about shooting conditions in plain language. Inverza's chat is powered by Anthropic Claude, Google Gemini, or OpenAI ChatGPT (bring your own key) or the built-in model, which runs Google's newest Gemini generation (currently Gemini 3.8 Flash). The chat can read the forecast, call tools to inspect specific hours or locations, and explain its reasoning. - **16 Condition Detectors.** Each detector ingests multiple forecast variables and returns a probability score and a time window. - **GPU-Accelerated Shadow Mapping.** See where light and shadow fall on the terrain at any time of day, computed from NASA SRTM elevation data on Apple's Metal compute kernels. Vector polygon overlays stay crisp at any zoom or 3D camera tilt (up to 85 degrees). At city zoom, real building shadows from OpenStreetMap outlines and tagged heights join the same time slider by default (a toggle can switch the layer off), showing which streets and squares catch light. To our knowledge no other photography planning app draws building shadows on the map; the AI uses the same building data to warn when a chosen photo subject sits in building shade. - **Photo Spot Map.** Discover viewpoints through geotagged photos, with sunrise, sunset, moonrise, and moonset direction lines overlaid on the terrain shadow map. With the shadow map active, two extra dotted lines track the current sun and moon position live as you scrub the time slider, so you can see exactly where light is coming from at any moment. - **AR Sky View (v1.5+).** Point the camera at the sky and see sun, moon, Milky Way core, and North Star paths drawn onto the live view, tracked with ARKit. Scrub through time to preview where the sky will be at any minute; switch between lenses by focal length to audition the exact frame before the event; a deep-red night mode protects dark adaptation. A Calibrate control corrects compass drift near metal or iron-rich rock. Live readouts (v1.6.4+) show how many degrees the sun, moon, and Milky Way core stand above or below the horizon. - **Horizon Paths (v1.5+).** The real 360-degree terrain horizon of any saved spot, computed from elevation data, with sun and moon arcs drawn across it. Read off the minute the moon or sun clears a specific ridge, remotely, weeks ahead. A Photographer/Subject toggle re-renders the horizon from either vantage. - **Horizon Paths 3D (v1.6+).** The same spot as an interactive SceneKit diorama: real terrain out to the surrounding peaks, OpenStreetMap buildings, trees and forests (individual trees, tree rows, woods, and orchards), lakes and rivers, and real coastlines with the ocean filled to sea level, under the sun and moon path circles drawn in the sky above the pin, in the same colours as the AR view. Building and mountain shadows, golden-hour tones, and phase-scaled moonlight all follow the time slider; the camera orbits around the photographer's or the subject's pin. Terrain, buildings, water, and vegetation reuse the app's existing elevation tiles and OpenStreetMap caches, so no new data source is needed. - **Find Alignments**: Search for Sun or Moon alignments by azimuth, elevation, date range, moon phase and adjustable photographer/subject heights. Use the controls or describe your photograph in Find with AI, review the settings, then calculate matching dates on your device. Matches describe geometry, not weather or guaranteed visibility. - **Save & Load Shooting Plans**: Save a shooting plan with its locations, heights, date, time, camera view, field of view, Find settings and notes. Load restores the setup, including its location. Plans stay on your device. - **Date-correct Moon Phase**: The Diorama shows the Moon’s illuminated phase and lit-side orientation for the selected time and location. - [Diorama shooting plans](https://inverza.app/#shooting-plans): Find / Load / Save workflow and screenshot. - **Solar Eclipse Planning (v1.6.3+).** The moon renders at its true apparent size for the date everywhere (its distance changes its disc by roughly -8% to +6% versus the sun), and every central solar eclipse through 2030 is bundled with official NASA/GSFC Besselian elements (eclipse predictions by Fred Espenak, NASA's GSFC). Scrub the Diorama to the eclipse and an exact obscuration percentage appears when the sun and moon discs overlap: it reads 100% only inside the true path of totality, accurate to the kilometre at the path edges. AR Sky shows the same overlap on the live camera for on-location framing. - **Photo Subjects (v1.5+).** Pair a saved spot with a separate subject pin up to 50 km away (peak, lighthouse, alpine hut, lake). OpenStreetMap classifies the subject into one of 22 kinds, the subject's own terrain horizon and light windows are computed, and distant subjects (>20 km) get a second forecast at their coordinates. - **Raw Weather Data & Interactive Charts (v1.5+).** A panel surfacing every raw forecast value behind the predictions over a 7-day timeline. Tap any value to explore it as an interactive chart with pinch zoom, weather condition markers, and day / golden-hour / night background shading tied to the real sunset geometry of the location. - **Raw Data Alerts (v1.5+).** Custom alerts on exact raw weather values: cloud base below the summit, wind under 10 km/h, fresh snow above 5 cm. Notifications are time-sensitive, so a dawn alert arrives even during Sleep Focus. - **Auto-Selected Regional Models.** Open-Meteo's best-match strategy consults the right model for each location: HRRR (3 km, hourly) in North America, ICON-D2 (2.2 km) and ICON-EU (7 km) in Europe, ECMWF IFS (~9 km) for medium-range globally, GFS (13 km) as a global fallback. 15-minute resolution where available. - **METAR Cross-Check.** Real-time ground truth from the nearest airport weather station (NOAA AWC), cross-referenced against model predictions. If the forecast says clear and the airport reports overcast, Inverza surfaces the discrepancy. Confirmed conditions are upgraded to a "Live" confidence tier. - **Marine & Water-Body Awareness.** Open-Meteo Marine sea-surface temperatures power coastal advection-fog detection (warm humid air over cooler seas - SF Bay, UK coast, Pacific Northwest). Inland lake and river water-temperatures are estimated from recent air-temperature history for steam-fog detection on calm autumn dawns. - **Aerosol & Air-Quality Data.** Hourly aerosol optical depth, PM10, and Saharan-dust readings (Open-Meteo Air Quality) feed Soft Light scoring - the dreamy particle-softened golden hour that requires fine material in the atmosphere to diffuse the sun without smothering it. - **Forecast Evolution.** Previous-run analysis compares what consecutive model runs predicted for the same hour. Drifting forecasts get a confidence penalty; stable predictions across many runs deserve more trust. - **Multi-Location Smart Alerts.** One alert can track several locations at once. Pick a rare condition (aurora, lenticular clouds), choose the spots you'd be willing to travel to, and Inverza notifies you whichever site lights up first. Push notifications, no ads, no tracking, no data resale. ## Pricing 14-day free trial, then $4.99 per year. One tier. Subscription is handled through the App Store and can be cancelled any time. ## Where it works iOS (iPhone). English, German, French, Spanish, Italian. Weather coverage is global, with higher-resolution output in Europe (ICON models) and North America (HRRR). --- # All 16 Conditions (https://inverza.app/conditions) ## Colorful Dawn (https://inverza.app/conditions/colorful-dawn) German: Morgenröte. The 20-40 minutes before sunrise can produce the most vivid skies of the day. When high-altitude cirrus and altocumulus clouds sit above a clear horizon, the sun - still below the horizon - lights them from below, painting intense reds, oranges, and magentas across the sky. Inverza detects this by analyzing the interplay of high cloud cover (the canvas), low cloud cover (which must be minimal so sunlight can reach the high clouds), humidity, and weather codes. When directional cloud data is available, it also checks whether the horizon toward the sunrise is clear - a wall of low cloud in that direction kills the color even if the sky overhead looks perfect. Since August 2026 it additionally ray-traces the twilight light path with cloud probes 150, 300, and 450 km along the sun's azimuth, counting at each probe only the layers tall enough to reach the grazing ray there, so a front hundreds of kilometres toward the sun dims the prediction before it can spoil the morning. Tip: Be in position well before the predicted time. The best color is fleeting and often peaks earlier than expected. Face east with a wide-angle lens, or isolate cloud patterns with a telephoto. FAQ: - When does a colorful dawn happen? 20-40 minutes before sunrise, when high clouds sit above a clear horizon and catch sunlight from below. The best color is usually 15-20 minutes before the sun actually rises. - What weather produces the best dawn colors? High-altitude cirrus or altocumulus cover, a clear horizon toward the east, low humidity, and no low clouds blocking the light. Inverza scores all of these automatically. ## Afterglow Sunset (https://inverza.app/conditions/afterglow-sunset) German: Abendrot / Nachglühen. Many photographers pack up right after sunset and miss the best part. The afterglow happens 10-25 minutes after the sun dips below the horizon, when high clouds continue to catch warm light from below. The colors can be even more intense than the sunset itself, shifting from gold through pink to deep purple. The detection mirrors Colorful Dawn but in reverse: Inverza checks for high cloud coverage, a clear horizon toward the sunset direction, low humidity, and dry weather. The condition uses the sun's geometric position (not terrain-adjusted), because atmospheric color depends on the sun's angle relative to the true horizon, not local mountains. Tip: Don't leave after sunset. Watch the sky for 20 more minutes. The afterglow often peaks when most people have already gone. Silhouettes against the glowing sky work beautifully. FAQ: - When does the afterglow peak? Roughly 10-25 minutes after the sun sets below the horizon. The exact peak depends on the sun's depression angle and the altitude of the high clouds catching the light. - Why is the afterglow sometimes stronger than the sunset? The sun is below the horizon, so its light travels through more atmosphere and reaches the high clouds from underneath, producing saturated pinks and purples you don't get while the sun is still above the horizon. ## Golden Clouds (https://inverza.app/conditions/golden-clouds) German: Goldene Wolken. Partial cloud cover during golden hour creates one of the most universally photogenic conditions. When 20-70% of the sky is covered by mid-level clouds, the low-angle sunlight catches their edges and underbellies, turning them golden. Too few clouds means a plain sky; too many blocks the sun entirely. Inverza scores the sweet spot of cloud coverage, checks for adequate visibility, and factors in wind speed (gentle wind creates more textured, dynamic cloud formations). Mid-level clouds get a scoring bonus since they catch golden light best. Tip: The golden hour window is short. Shoot within 30 minutes of sunrise or sunset. Use the clouds as a compositional element - they add drama to any landscape. FAQ: - What cloud cover produces golden clouds? 20-70% is the sweet spot - enough clouds to catch the light, but with gaps for the sun to reach them. Mid-level clouds (altocumulus, altostratus) score higher than purely low or high clouds. - How long does the golden cloud window last? Usually under 30 minutes, centered on sunrise or sunset. Colder-season golden hours last longer because the sun moves across the sky at a shallower angle. ## Ground Fog (https://inverza.app/conditions/ground-fog) German: Bodennebel. Ground fog creates an ethereal, otherworldly atmosphere - a thin blanket hugging the surface while everything above stays clear. It forms when humidity is very high (90%+), wind is nearly calm, and the air temperature drops close to the dew point. These conditions are most common in autumn and early winter during the pre-dawn hours. Inverza watches for the triple convergence of high humidity, low wind speed, and a minimal temperature-dew point gap. Calmer winds and tighter temperature gaps score higher, as they indicate denser, more stable fog formation. This classic radiation-fog path remains the default whenever no body of water is nearby. Near coastlines, lakes, and large rivers, two additional fog physics activate. Coastal advection fog forms when warm humid air flows over a cooler sea - Inverza pulls real sea-surface temperature from the Open-Meteo Marine API and triggers when the air is 2-10 °C warmer than the sea, wind is 4-30 km/h, and the wind direction is onshore (within ±60° of the water-to-observer bearing). Typical along the UK coast, San Francisco Bay, and the Pacific Northwest in summer. Steam fog (evaporation fog) is the opposite case: cold dry air over a warmer lake or river produces visible vapour ribbons rising off the surface. Inland water temperature is estimated as a 3-day trailing mean of recent air temperature; steam fog triggers when water is 4-12 °C warmer than air and wind is below 6 km/h. The water-body lookup is fail-silent - any source failure quietly reverts the detector to the radiation-only path. Tip: Shoot from elevated viewpoints looking down into the fog. Low-angle light from sunrise or sunset crossing the fog layer creates beams of light (crepuscular rays) and dramatic contrast. For coastal advection fog, position yourself upwind of where the air meets the cold water - that's where the layer is thinnest. For steam fog, get low and shoot horizontally across the lake so rising vapour catches sidelight from the just-risen sun. FAQ: - When does ground fog form? Usually in the pre-dawn hours after a clear, calm night when the ground has radiated heat away and air near the surface cools to the dew point. Most common in autumn. - Ground fog vs. valley fog vs. cloud inversion? Ground fog is a thin layer right at the surface. Valley fog fills a basin. Cloud inversion is a much thicker layer that can be seen from above, often filling entire valleys while ridges stay clear. - How does the water-aware fog detection work? Coastal advection fog uses real sea-surface temperature from Open-Meteo Marine and triggers when warm humid air flows over a cooler sea with onshore wind. Steam fog uses a 3-day air-temperature mean as a lake/river temperature proxy and triggers on calm mornings when the water is warmer than the air. Both add to the radiation-fog score rather than replacing it. - What if I'm nowhere near water? The radiation-fog detection runs unchanged. Water-aware branches only activate when a coastline is within ~10 km or a sizeable lake/river within ~3 km. ## Hoarfrost (https://inverza.app/conditions/hoarfrost) German: Raureif. Hoarfrost is the intricate white ice crystals that coat branches, grass, and fences after a cold, calm, humid night. It looks like nature has dipped everything in powdered sugar. The crystals form by deposition - water vapor skipping the liquid phase and freezing directly onto surfaces that have dropped below freezing. Inverza detects hoarfrost formation by evaluating sub-freezing temperatures (ideally -3 C to -10 C), very high humidity, near-calm wind, and clear skies that allow strong radiative cooling. Clearer skies score higher because they let surfaces radiate heat away into space, dropping their temperature faster than the air. Tip: Shoot at first light before the sun warms the crystals and they disappear. A tripod and macro lens reveal the crystal geometry; wide-angle shots capture the effect at landscape scale. FAQ: - When does hoarfrost form? Clear, calm, humid nights with sub-freezing temperatures (-3 C to -10 C is ideal). Autumn and early winter, most often after a wet spell. - Hoarfrost vs. regular frost? Hoarfrost forms from water vapor direct-depositing onto a surface as ice crystals, producing larger feathery shapes. Regular frost is frozen dew - water droplets that condensed first, then froze. ## Aurora Borealis (https://inverza.app/conditions/aurora) German: Polarlicht. The northern lights are the most spectacular atmospheric phenomenon visible to the naked eye. They happen when charged particles from the sun interact with Earth's magnetosphere, exciting oxygen and nitrogen atoms high in the atmosphere to emit light. Aurora is most common near the Arctic Circle, but strong geomagnetic storms can push it down to mid-latitudes. Inverza combines the NOAA SWPC Kp forecast with your location's magnetic latitude to calculate aurora visibility probability. It then checks cloud cover, moonlight, and whether the timing aligns with astronomical darkness. A bright full moon can wash out all but the strongest displays. Tip: Face north, use a wide-angle lens at f/2.8 or faster, ISO 1600-6400, and 5-15 second exposures. Check the Kp forecast for timing - aurora activity shifts quickly. FAQ: - How far south can aurora be seen? Kp 5 can reach Scotland, southern Canada, and the northern US. Kp 7+ has been seen as far south as Germany, France, and the central US. Most mid-latitude sightings are geomagnetic storms following a coronal mass ejection. - What is Kp? Kp is a planetary geomagnetic index from 0 to 9. Higher Kp means aurora is visible further from the pole. Inverza pulls NOAA's 3-day and 30-minute Kp forecasts automatically. ## Fresh Snow and Clear Sky (https://inverza.app/conditions/fresh-snow) German: Frischer Schnee. Fresh, unbroken snow under a clear blue sky is one of the most classic winter landscape conditions. The snow reflects blue from the sky in shadows and glows gold in the warm low-angle winter sun. Trees, rocks, and fences become graphic elements against the white canvas. Inverza detects this by watching for recent snowfall (over the past hours), clearing skies, and sub-freezing temperatures that keep the snow powdery. The condition is strongest shortly after the storm clears - before foot traffic, wind, or melting disturb the surface. Tip: Get out early before the snow is tracked. Aim for morning or late-afternoon light when the long shadows reveal texture. Manual exposure compensation of +0.7 to +1.3 keeps the snow looking white, not grey. FAQ: - How soon after snowfall is best? Within a few hours of the storm clearing, before wind drifts or sun starts to melt. Inverza scores the combination of recent snow and improving sky. - Can Inverza tell when snow will stick? It considers temperature, snowfall amount, and surface temperature context. If you need fresh snow for a shoot, watch the condition's time window rather than just the precipitation forecast. ## Dramatic Storm Clouds (https://inverza.app/conditions/dramatic-storms) German: Dramatische Wolken. Storm fronts and isolated cells produce some of the most dramatic skies in landscape photography. Towering cumulonimbus, mammatus on the underside of anvil clouds, rain shafts lit by sunlight, and the post-storm rainbow all happen during and after convective weather. Inverza watches for unstable atmospheric conditions, significant cloud development, and the specific weather codes associated with thunderstorms, showers, and frontal passages. It also flags the window just before a storm arrives (dramatic build-up) and just after (clearing with lingering drama and potential rainbows). Tip: Safety first - storms can produce lightning, hail, and flash floods. Stay off exposed peaks and ridges. Shoot from safe vantage points. A polarizer deepens the sky and pulls out cloud texture; a graduated ND tames the sky-to-ground contrast. FAQ: - When are dramatic storm clouds best for photography? The hour before a storm arrives (build-up with low-angle light) and the hour after it passes (clearing with rainbows and dramatic light shafts) usually beat the storm itself for landscape work. - Is it safe to photograph storms? Keep distance, avoid high ground and open spaces, and never shelter under isolated trees. Inverza surfaces the condition so you can plan a safe vantage point in advance. ## Cloud Inversion (https://inverza.app/conditions/cloud-inversion) German: Wolkeninversion. Cloud inversion is the condition that inspired Inverza's name. It creates a sea of clouds filling valleys while mountain ridges rise above like islands. It happens when cold, humid air pools in valleys overnight under a temperature inversion: the air at lower elevations is colder and more humid than the air above, trapping moisture in a dense, photogenic layer. The detector evaluates humidity (85%+), calm winds (below 5 km/h), and temperature inversion strength between valley floor and ridge. A stronger inversion means the cloud layer stays more distinct and photogenic. Tip: Hike to a ridge or summit before sunrise. The combination of a cloud inversion with the warm light of dawn is one of the most rewarding scenes in landscape photography. This is why we built Inverza. FAQ: - What causes a cloud inversion? A temperature inversion where cold humid air is trapped below warmer air above. Valleys fill with cloud while ridges stay clear, creating the characteristic "islands in a sea of clouds" look. - When are cloud inversions most common? Clear calm nights in autumn and winter, especially after wet weather. The condition typically peaks in the hour before and after sunrise before the sun burns off the layer. ## Milky Way (https://inverza.app/conditions/milky-way) German: Milchstraße. The galactic core is visible from April through September in the northern hemisphere, arching across the southern sky. Capturing it requires a dark sky, astronomical darkness (no twilight), clear air, and a moon that is either absent or only a crescent. Inverza models all of these: moon phase and position, sun depression for true astronomical darkness, cloud cover, humidity, and the galactic core's altitude above the horizon. It tells you when the core is up, how dark the sky really is, and whether the weather will cooperate. Tip: Use a wide, fast lens (14-24 mm f/2.8 or faster). ISO 3200-6400, 15-25 seconds, manual focus on a bright star. Escape light pollution - even a small town can wash out the core. Plan around the new moon. FAQ: - When is the galactic core visible? April through September in the northern hemisphere, peaking in June-July. Best seen during astronomical darkness (sun more than 18 degrees below the horizon) with no moon. - Does Inverza account for light pollution? It models weather, moon, and twilight precisely. Light pollution depends on your location, so pick a dark-sky site and Inverza will tell you when to shoot. ## Belt of Venus (https://inverza.app/conditions/belt-of-venus) German: Venusgürtel. The Belt of Venus is a soft pink band that appears opposite the sun at dawn and dusk, above the dark blue shadow of the Earth rising against the atmosphere. It is visible in the 10-25 minutes around sunrise and sunset when the horizon is clear and the sky is not dominated by clouds. Inverza detects this by checking for low cloud cover, a clear horizon, and the specific solar geometry that produces the effect. A fully clear sky scores highest because the pink band has the atmosphere itself as its canvas. Tip: Face away from the sun. A telephoto compresses the pink band against distant mountains. A wide-angle captures the full arc of the sky. Include water or snow for reflected pink tones. FAQ: - When is the Belt of Venus visible? 10-25 minutes after sunset and 10-25 minutes before sunrise, opposite the sun, when the sky is mostly clear. - What causes the Belt of Venus? Sunlight scattering off the higher atmosphere creates the pink; Earth's own shadow projected onto the atmosphere makes the dark blue band below. You are literally photographing Earth's shadow in the sky. ## Reflecting Waters (https://inverza.app/conditions/reflecting-waters) German: Spiegelnde Wasser. Still water creates a perfect mirror of the landscape. The effect is most dramatic when the reflected scene is itself interesting (sunrise colors, mountains, dramatic clouds) and the water surface is undisturbed. Inverza watches for very calm wind at water level, clear or photogenic skies for the reflection to capture, and the right time of day. Dawn and dusk are best; glare from a high sun washes the reflection out. Tip: Shoot close to the water surface - the lower your angle, the more of the reflection you include. A polarizer reduces surface glare but also kills the reflection; use it sparingly. Exposure-blend the sky and water if the dynamic range is too wide. FAQ: - How calm does the water need to be? Essentially windless. Even a light breeze breaks the reflection. Inverza flags the hours when wind speed is below the threshold for mirror-smooth water. - Best time of day for reflections? Dawn and dusk. The low-angle light illuminates the reflected scene, and the light tends to be calmer in the early and late hours. ## Soft Light (https://inverza.app/conditions/soft-light) German: Weiches Licht. Soft, diffused light under overcast or high-cloud cover is a photographer's best friend for intimate landscape scenes, forests, and waterfalls. It removes harsh shadows, saturates colors, and reveals detail in texture and foliage. Inverza detects this by watching for full cloud cover (or near-full), reasonable visibility, and the absence of rain. Mid-day shooting - usually considered a dead time in clear conditions - becomes productive when the sky is an even soft-box. Tip: Waterfalls and stream photography shine in soft light. Use a polarizer to cut reflection on wet rocks. A 1/4 - 1 second shutter gives silky water without going too far. FAQ: - When is soft light available? Any overcast day, at almost any time. Most useful mid-day when direct sun would be harsh. - What subjects work best in soft light? Forests, waterfalls, streams, intimate scenes, detail shots, and anything with reflective wet surfaces. ## Full Moon Silhouette (https://inverza.app/conditions/full-moon-silhouette) German: Vollmond-Silhouette. A full moon setting behind a mountain ridge or rising over a landscape creates one of the most iconic compositions in photography. The key is timing: the moon must be at or near full, rising or setting during twilight so the landscape is still lit, and the atmosphere must be clear. Inverza models moon phase, rise and set times, altitude and azimuth, and the brightness of the surrounding sky. It flags the narrow window where a full or near-full moon meets a balanced sky. Tip: Telephoto compression (200-600 mm) brings the moon in dramatically behind distant peaks. Plan the shot geographically in advance - the moon rises in a specific direction only on a specific date. Inverza's direction lines help. FAQ: - When does the full moon rise and set relative to sunset? The full moon rises around sunset and sets around sunrise. This gives the best landscape-plus-moon window - moonrise against a still-lit sky, or moonset against pre-dawn light. - How do I plan a moon-behind-peak shot? Use Inverza's azimuth line to see where the moon will rise or set from your chosen viewpoint, then find a date when that line intersects a peak. The window is often just a minute or two. ## Brocken Spectre (https://inverza.app/conditions/brocken-spectre) German: Brockengespenst. The Brocken spectre is the photographer's own shadow projected onto a cloud or fog layer below, often surrounded by a colorful "glory" of concentric rings. It requires the photographer to be above a cloud or fog layer with the sun behind them. Inverza detects the setup conditions: a cloud inversion or fog bank below, a clear sun in the 2-20° altitude band, and SRTM elevation above the cloud layer (METAR-confirmed when an airport is nearby; forecast-based otherwise via low-cloud cover, humidity, and visibility). Critically, the detector also checks whether you're standing on open terrain. A forested mid-altitude summit can have all the right atmospherics but the surrounding trees block low sun and break the projected shadow - the spectre simply doesn't form. Inverza queries OpenStreetMap landcover at the exact spot: tags like natural=bare_rock, scree, cliff, fell, or glacier earn full confidence; tags like natural=wood or landuse=forest drop the score below the surfacing threshold so a forested location never produces a false-positive Brocken alert. Where OSM has no relevant polygon (or the lookup fails), the app falls back to a latitude-aware tree-line estimate (~2,250 m in the Alps, ~1,300 m in the Scottish Highlands, ~1,200 m in Norwegian fjords, sea level above 70°N) compared against your SRTM elevation. The phenomenon is rare, so when the conditions align - geometric, atmospheric, AND vegetation-wise - the alert matters. Tip: Hike above the cloud layer on a morning with a strong inversion. Stand with the sun directly behind you. The spectre appears in your shadow's head on the cloud below. The glory rings around it are caused by diffraction through water droplets. FAQ: - When can I see a Brocken spectre? Above a cloud layer or fog bank with the sun behind you, on open terrain (ridge, summit, exposed outcrop - not in forest). Most common during a cloud inversion in the mountains. - Named after a real place? Yes, the Brocken is the highest peak in the Harz mountains of Germany, where the phenomenon was first scientifically described. - Why does the detector care about forest cover? Trees block low sun and clutter the projected shadow, so the spectre doesn't form in dense forest even when atmospherics are perfect. Inverza checks OSM landcover and a latitude-aware tree-line so forested locations never trigger false-positive alerts. ## Lenticular Clouds (https://inverza.app/conditions/lenticular-clouds) German: Lenticularis-Wolken. Altocumulus lenticularis are smooth, lens-shaped clouds that appear stationary over or downwind of a prominent mountain ridge. They form when stable, moist air is forced up and over the ridge, generating a standing wave on the lee side where moisture condenses at the wave crest. The cloud looks frozen in place because air is constantly flowing through it. At sunrise and sunset they often glow orange and pink, stacked like UFOs above the peaks. Inverza combines SRTM terrain analysis with pressure-level atmospheric data (700 hPa or 500 hPa depending on ridge altitude) to predict this condition with precision. It identifies the dominant ridge within 30 km of the observer, requires at least 400 m of prominence, then evaluates four factors: ridge-top wind speed (25+ km/h, ideal 45), wind perpendicularity to the ridge, atmospheric stability (lapse rate below 6.5 K/km between 700 and 500 hPa), and humidity in the 55-85% sweet spot at crest altitude. A lee-side observer bonus adds the final 10%. Without pressure-level data or enough terrain prominence, the detector stays silent rather than firing false positives. Tip: Position yourself on the lee side of the ridge - downwind from the peak - for the cleanest view of the stacked lens shapes. Sunrise and sunset transform them into glowing silhouettes. Telephoto compresses the stack; wide-angle captures the wave pattern. The cloud often lasts hours, giving you time to explore compositions. FAQ: - What causes lenticular clouds? Stable, moist air forced over a mountain ridge creates a standing wave on the lee side. Moisture condenses at the wave's crest, producing a smooth, lens-shaped cloud that appears stationary because the air flows through it continuously. - Why are lenticular clouds so rare? They need a specific combination: a prominent ridge, strong wind blowing perpendicular to it, a stable atmospheric layer that holds the wave together, and just-right humidity at ridge-top altitude. Inverza scores all four factors simultaneously, which is why it can predict them hours in advance. --- # Press Kit (https://inverza.app/press) ## Product facts - Product: Inverza - Category: Photography, Weather - Platform: iOS (iPhone) - Price: 14-day free trial, then $4.99/year - App Store: https://apps.apple.com/app/id6760370838 - Developer: Marcel Strelow (Germany) - Release: 2026 - Languages: English, German, French, Spanish, Italian ## Short boilerplate Inverza is an iOS app that uses AI and multi-model weather data to predict sixteen photo-worthy conditions for landscape photographers. ## Medium boilerplate Inverza is a landscape photography weather app for iOS. It blends multiple forecast models, real-time airport observations, pressure-level atmospheric data, and NASA elevation data to predict sixteen photo-worthy conditions - from colorful dawn and cloud inversions to aurora borealis, Brocken spectres, and lenticular clouds over mountain ridges. An ARKit-powered AR Sky view draws sun, moon, and Milky Way paths onto the live camera feed so compositions can be locked before the event, and a Horizon Paths chart plans them remotely against the real terrain horizon of any spot. One tier: 14 days free, then $4.99 per year. ## Quotable claims (free to lift, each backed by the fact that follows) - "The Swiss Army knife of weather apps for photographers." One $4.99/year subscription covers forecasting, 16 condition detectors, AR composition previews, terrain horizon charts, GPU shadow mapping, photo spot discovery, raw data charts, and custom alerts; there is no feature tier above it. - "The only weather app we know of that combines AR, AI, and photo spot planning with AI-powered condition detection." Planning apps do geometry, model browsers show raw weather, a handful of apps detect conditions; Inverza is, to our knowledge, the only one doing composition (AR Sky, Horizon Paths), interpretation (16 detectors with confidence tiers), and conversation (AI chat) in a single tool. - "Where generic weather apps answer 'will it rain?', Inverza answers 'will the light be worth getting up at 4 a.m.?'" - "An interpretation engine, not a model browser." Eight data streams blended into one answer: should I go? - "Sixteen conditions most weather apps have never heard of." Brocken spectre, Belt of Venus, cloud inversion, lenticular clouds, hoarfrost, afterglow, Milky Way visibility, and more. - "It can tell you the minute the moon clears a specific ridge, weeks in advance." Horizon Paths computes the real terrain horizon from elevation data; AR Sky previews the exact frame on location, per lens. - "No server, no account, no ads." Inverza has no app-operated backend. Saved spots are stored locally; API keys are kept in Keychain and sent only to their provider. AI chat shares relevant conversation, location and planning context after permission. Gemini chat requires an 18+ confirmation. No in-app ads or cross-app tracking SDK. - "Built by one landscape photographer, in the Alps, for his own camera bag." ## Founder quote (free to use) "I started Inverza because I wanted exactly one thing: an alert that wakes me up when a fire sky is coming. Then I just kept building every feature I personally wished existed and couldn't find anywhere - the AR view to frame a shot before the sky delivers it, the horizon charts, the raw data graphs. It's the app I always wanted in my camera bag, and I'm the heaviest user of every feature in it." - Marcel Strelow, founder and developer ## Story angles - The alert that became an app: a one-person product shaped entirely by personal use. - Planning vs. the moment: does forecasting the light kill the magic, or buy presence in the field? Adams' unmetered ninety-second Moonrise as the preparation story in disguise. - An indie app marketed with a short film: "Stealing Moonrise", an AI-made (and labelled) film in which a time-travelling photographer tries to take the world's most famous landscape photo an hour before Ansel Adams. - Weather apps grow up: from model browsers to interpretation engines, with Inverza as the photography-niche case study. ## Press contact Marcel Strelow, founder and developer. Email: contact@inverza.app. We aim to reply to press inquiries within two business days. Review codes and embargoed information are available on request. --- # Privacy summary (https://inverza.app/privacy) Inverza collects minimum data required to function. Weather queries go to public weather APIs. No ads, no third-party tracking, no data resale. Full policy: https://inverza.app/privacy. # Terms summary (https://inverza.app/terms) Inverza is provided as-is for photography planning. Do not rely on it for safety-critical decisions. Subscription is handled by Apple via the App Store. Full terms: https://inverza.app/terms. # Legal notice (https://inverza.app/impressum) Responsible party: Marcel Strelow, Triftstr. 43, 82467 Garmisch-Partenkirchen, Germany. Email: contact@inverza.app. --- # Blog (https://inverza.app/blog) ## The anatomy of a rainbow (https://inverza.app/blog/the-anatomy-of-a-rainbow) Published: 2026-09-13. Category: Light & optics. By Marcel Strelow. Companion film: Physics Says You Cannot Steal a Rainbow. I Went Back to 1981 to Try Anyway. (https://www.youtube.com/watch?v=2he2zjNz0MQ). Published 2026-08-20; duration 5m15s. A scene from Nigel North's AI-made journey to Lhasa. This is an illustration from the episode, not Galen Rowell's original photograph. ### The photograph that took a mile Galen Rowell's Rainbow over the Potala Palace has the sort of alignment that makes you wonder how long someone waited for it. A bright band of colour arrives at a palace, the building catches the sun, and the mountains behind it sit in darkness. Everything seems to have found its place. In October 1981, in Lhasa, Tibet, Rowell saw the rainbow and ran nearly a mile to put it where he wanted it in the frame. Dick Dorworth, who was there, confirms the story in his recollection of Rowell (https://tahoequarterly.com/fall-2024/galen-rowell-a-dynamic-mountain-light-remembered). The weather supplied the light. Rowell supplied the viewpoint. That is the part I wanted to explore in the next Nigel North film. We spend a lot of time deciding when to take a photograph. A rainbow makes the question of where to stand wonderfully literal. ### Nigel goes back to 1981 In Physics Says You Cannot Steal a Rainbow. I Went Back to 1981 to Try Anyway., Nigel takes a film camera, an outfit for the era, and one fairly substantial cheat: a phone with Inverza on it. He has five minutes of screen time to learn what Rowell understood, cope with the altitude, and negotiate with a dog. It follows the same idea as our journey to Ansel Adams' Moonrise (https://inverza.app/blog/plan-the-frame-to-the-minute): use a little fictional time travel to look closely at a real photograph and the science behind it. The character and historical scenes are made with AI. Rowell's photograph and his achievement are real; you can explore his work through Mountain Light (https://www.mountainlight.com/). Watch Nigel North's rainbow episode · 5 min 15 sec. If the player does not load, watch it on YouTube (https://www.youtube.com/watch?v=2he2zjNz0MQ). ### What happens inside a raindrop Sunlight bends as it enters a raindrop. Some of that light reflects from the back of the drop, then bends again on its way out. Water bends the different wavelengths by different amounts, spreading white sunlight into colours. For the primary rainbow, the route involves two refractions and one internal reflection. The Royal Meteorological Society explains that journey (https://www.rmets.org/metmatters/how-are-rainbows-formed) in more detail. The light leaving many drops is concentrated around particular viewing angles. The red outer edge of the primary bow sits roughly 42° from the direction directly opposite the sun; violet is nearer 40°. That direction is called the antisolar point. If your shadow is visible, the shadow of your head points towards it. The National Weather Service's rainbow guide (https://www.weather.gov/fgz/Rainbow) explains the colour order and the geometry. Picture a cone with its tip at your eye and its axis pointing away from the sun. Raindrops along that cone send the rainbow light you see. As you move, a different set of drops supplies it. Steven Businger's study of rainbow science and photography (https://doi.org/10.1175/BAMS-D-20-0101.1) describes this observer-centred geometry. It explains why a rainbow has no fixed landing place in the field, and why two people standing apart see slightly different bows. For composition, that is useful. Moving sideways changes the palace's direction from your camera while the bow remains tied to the sun's direction. You can bring the two together, provided there is still sunlit rain in the right part of the view. Rowell's run was a photographic decision with an optical explanation. ### The useful number is 42° The sun's height tells you approximately how high the primary bow can reach. When the sun is 10° above the horizontal, the antisolar point is 10° below it. Add the bow's roughly 42° radius and its red outer edge tops out around 32° above the horizontal. One angle to take into the field Top of the bow ≈ 42° − sun height Sun 10°above the horizontal Bow's centre −10°below the horizontal Top of the bow 32°above the horizontal An approximate primary-rainbow calculation. Terrain can hide part of the arc; rain and direct sunlight still have to meet. A lower sun gives you a taller arch. As the sun approaches the horizon, the bow approaches a semicircle above a level horizon. Above about 42° sun elevation, the primary bow lies below the horizontal, so it disappears from an ordinary ground-level view. From a high viewpoint, with sunlit droplets below you, you can see more of the circle, sometimes all of it. These are the same viewing angles, with more of the scene available beneath your feet. See the NWS low-sun explanation (https://www.weather.gov/fgz/Rainbow) and Businger's full-circle examples (https://www.soest.hawaii.edu/MET/Faculty/businger/PDF/The%20Best%20Rainbows%20on%20Earth.pdf). This gives you a useful first check for a location: a low sun behind you, rain in front of you, and sunlight reaching that rain. You can be standing in shade and still see a rainbow. The droplets are the part that needs direct light. ### The second bow and the dark band Sometimes a fainter bow appears outside the first. Its light has reflected twice inside the drops, and its colours run the other way: red on the inside, violet on the outside. It sits roughly 50–53° from the antisolar point. The space between the two bows often looks darker. This is Alexander's dark band: the primary and secondary rainbow paths send much less light back towards you at those intervening angles. The sky and clouds still contribute light, so the band is darker rather than black. Roland Stull's chapter on atmospheric optics (https://www.eoas.ubc.ca/books/Practical_Meteorology/prmet/Ch22-Optics.pdf) walks through both effects. That darker sky can do a lot for a photograph. Try giving the second bow room in the frame before zooming in on the brightest part. Then look at the foreground: a small patch of sunlit grass or stone may be enough to connect all that sky to a place. ### Planning your own rainbow photograph The useful forecast is a combination of things: showers, a break for the sun, and a subject in the right direction. Evening rain to your east with a low western sun is a classic arrangement. Morning reverses it. Rainbows can happen with ordinary showers too; a thunderstorm is not required. Inverza helps put those pieces together. Horizon Paths shows the sun's direction and elevation against the terrain at your chosen spot. The weather forecast adds the likely rain and cloud pattern. In relevant storm guidance, AI Chat can also point out possible rainbow geometry, including a low-sun time and the direction opposite it. That is a candidate to investigate: the app cannot know the exact position of every shower or promise when a rainbow will appear. - Choose a subject and leave room to move. Save a spot with a view towards the expected rain. Look for a few possible camera positions around your building, tree or mountain. - Check the sun in Horizon Paths. Find a time when it is low behind you. Use 42° minus its elevation to estimate the top of the bow, then think about how much sky the frame needs. - Ask about the overlap. Try AI Chat with: “Could showers and low sunlight overlap here this afternoon, and which direction should I watch for a rainbow?” Read the answer alongside the forecast, then check current radar and the actual sky as the time approaches. - Make the alignment on location. When a bow appears, take a frame, then move if a better relationship with the foreground is possible. Check the bright colours and sunlit surfaces for clipped highlights. A wider photograph first gives you something to keep while you work on a tighter composition. If thunder is audible, take shelter in a substantial building or an enclosed hard-topped vehicle. A rainbow can appear while lightning is still a hazard; the National Weather Service's lightning guidance (https://www.weather.gov/safety/lightning) applies even when your part of the sky has cleared. This is what interests me about Rowell's photograph, and why it belongs in a film about planning. Understanding the light gave him a reason to move. His eye told him when to stop. Try it with a familiar place next time showers are forecast. Check the sun, look towards the rain, and see what a few steps do to the picture. Nigel's trip to 1981 (https://www.youtube.com/watch?v=2he2zjNz0MQ) is there if you would like a dog and a little time travel with the explanation. ### Visual guide: inside a raindrop The article includes a labelled spherical-drop ray diagram: (1) light refracts into the water, (2) some reflects from the back of the drop, (3) light refracts out again. Representative red-to-violet paths are traced using Snell’s law with no exaggerated colour separation. See https://www.atoptics.org.uk/rainbows/primrays.htm for the geometric-optics explanation. ### Interactive visual: sun height and the rainbow angle A side-view diagram places the sun behind the observer, marks the horizontal, and shows the 42-degree primary-bow angle measured from the antisolar direction. An accessible sun-height slider covers 0 to 50 degrees. At a sun elevation of 10 degrees, the antisolar direction is -10 degrees and the primary bow’s top is 32 degrees above the horizontal. At 42 degrees, its top reaches the horizontal; above this it lies below. A high viewpoint may still reveal sunlit droplets below the horizontal. The illustration shows geometry, not a guarantee of rain or visibility. The static 10-degree example remains visible without JavaScript. ## A moving picture is worth ten thousand words - so we made one (https://inverza.app/blog/watch-inverza-in-60-seconds) Published: 2026-04-16. Category: Inside Inverza. A moving picture is worth ten thousand words - so instead of another screenshot, we made one. Sixty seconds, vertical, no voice-over, no buzzwords. Just Inverza doing what it does every morning. The Short walks through the four things that separate Inverza from a generic weather app: AI Weather Chat answering a plain-English question ("will tomorrow morning be worth the drive to the lake?"); condition detection picking up a cloud inversion forming overnight, with a confidence score and a time window; shadow mapping showing which side of the ridge will catch first light, computed from the terrain, not guessed; and the photo spot map pulling geotagged photographs and drawing the sunrise and sunset direction lines over the shadow map. Why vertical: Inverza is an iPhone app. Everything in the clip is the actual app, in actual use, at actual resolution. Shot on-device, exported vertical, posted as a Short so it plays inline when shared. Watch on YouTube Shorts: https://www.youtube.com/shorts/DIwtkxOgowA ## The galactic core is back - what that actually means for European photographers (https://inverza.app/blog/galactic-core-returns-to-europe) Published: 2026-04-16. Category: Milky Way. If you opened Inverza in the last few days and saw the Milky Way detector score above zero for the first time since last September, that is not a bug. The galactic core is back. For European photographers, that is a bigger deal than it sounds. Why the core disappears for half the year: the bright textured part of the Milky Way - the galactic center in Sagittarius - is visible only when two conditions overlap: the core has to be above the horizon, and the Sun has to be at least 18 degrees below it (astronomical darkness). From November through February in Europe, those never overlap. From early April the geometry shifts: the core starts rising late at night. By June-July it crosses the meridian around midnight. By September it sets earlier and earlier, and by October it is done again. European Milky Way season is roughly mid-April to late September, minus the Moon, weather, and (above 60 N) summer twilight. How low it stays: from 48 N (Alps, southern Germany, northern Italy) the core rarely climbs above 18-22 degrees at its meridian transit. From 52 N (Berlin, Amsterdam) it peaks around 15 degrees. From 60 N (Oslo, St Petersburg) it barely clears 7 degrees. Low altitude means more atmospheric extinction, more scattering, and dependency on a clean southern horizon. Southern hemisphere comparison (25-35 S: Sydney, Santiago, Cape Town): the same core passes nearly directly overhead, at some tropical southern latitudes transiting the zenith. The practical version: in Europe the Milky Way is a horizon subject; in the southern hemisphere it is an overhead subject. The two look and behave completely differently. Northern Europe (45-55 N) characteristics: season April-September with a gap in midsummer at high latitudes. Peak altitude 15-22 degrees. Core sits low in the south. Large Magellanic Cloud, Small Magellanic Cloud, Carina Nebula, Alpha/Beta Centauri, and the Southern Cross are all permanently invisible. Southern hemisphere (25-35 S) characteristics: effectively year-round visibility with peak altitude in May-August (their winter). Peak altitude 70 degrees to near-zenith. Core nearly overhead, with the "Emu in the Sky" dark lane visible end-to-end. Magellanic Clouds, Carina, Coalsack, Jewel Box visible exclusively from here. Why the view differs: orientation - from Europe, Sagittarius rises SE, climbs S, sets SW, axis nearly parallel to horizon; from the south, it rises E, passes overhead, sets W, rotating across the night. Brightness - a southern observer at zenith shoots through one atmosphere's worth of air; a northern observer at 20 degrees shoots through roughly three, with three times the molecular scattering, aerosol, and low-lying light pollution path. And companions - the Magellanic Clouds (two satellite galaxies of the Milky Way) are never visible from Europe; Carina Nebula, probably the brightest emission nebula in the sky, never rises for us; the Southern Cross, Omega Centauri, and the Coalsack are all permanently below the European horizon. European planning recommendations: commit to new-moon weekends (about six per year in season); pick a site with a clean southern horizon; go higher (Alps, Dolomites, Pyrenees, Canaries, Scottish highlands); use the Inverza Milky Way detector (sun depression, moon, cloud, humidity, core altitude); consider a trip south (Namibia, La Palma, Atacama, Tekapo) for the year-round zenith core. European monthly cheat-sheet: April - core only in the last hour before astronomical twilight, low and short; May - core well up before dawn, decent altitude from mid-latitudes; June-July - core crosses meridian near midnight, best altitude of season, but above 57 N you lose darkness; August - core high right after dusk, dropping through the night, most productive month; September - core sets early, last chance until April, often the most transparent air. ## Plan the frame to the minute: Horizon Paths at home, AR Sky in the field (https://inverza.app/blog/plan-the-frame-to-the-minute) Published: 2026-07-16. Category: AR Sky. Companion film: "Stealing Moonrise" on YouTube: https://www.youtube.com/watch?v=QecijG_ooNs Ansel Adams took Moonrise, Hernandez on November 1, 1941 in about ninety seconds, with no meter reading and one sheet of film, and could never remember exactly when; an astronomer recovered the date and minute of exposure from the moon's position in the frame fifty years later. The geometry of the moment was knowable the whole time. The post pairs this story (and Inverza's AI-made short film Stealing Moonrise, in which a time-travelling photographer arrives an hour before Adams) with Inverza's two-part composition-planning workflow. Part one, remote (Horizon Paths): save a spot anywhere on the map; Inverza computes the terrain silhouette for that point from elevation data and draws the sun's and moon's arcs across it. Read off the minute the moon clears a specific ridge, where along the horizon it happens, and what the sun is doing at that same minute. Moonrise-style photographs are a two-body problem: the shot lives in the short overlap window where the moon is up in the east and the low western sun still lights the foreground. The Photographer/Subject toggle handles cases where camera position and foreground have different horizons. Part two, on location (AR Sky, new in Inverza 1.5): point the phone at the scene and sun, moon, and Milky Way are drawn onto the live camera feed, ARKit-anchored. The time scrubber jumps to the planned minute so the moon marker hangs exactly where the moon will be; walk until the marker sits where the composition wants it. Lens switching by focal length previews different crops of the same scene before anything happens in the sky. Caveat: phone compasses drift a degree or two near metal; a Calibrate control nudges the overlay. Workflow summary: drop a spot from home; find the overlap window in Horizon Paths; closer to the date, let the condition detectors confirm the sky will cooperate; arrive early, scrub AR Sky to the planned minute, position, choose focal length, plant the tripod; wait. ## Chasing the shadow: how to plan and photograph solar eclipses through 2030 (https://inverza.app/blog/photographing-solar-eclipses-through-2030) Published: 2026-08-14. Category: Eclipses. Total vs. annular: every solar eclipse is the moon passing exactly between observer and sun; the outcome is decided by the moon's distance that day. Near perigee the moon appears about 6% larger than the sun and covers it completely (total eclipse: twilight, corona, filter off for the minutes of totality). Near apogee it appears about 8% smaller and leaves a blazing ring of sunlight (annular eclipse, the "ring of fire": sky never darkens, filter never comes off). Since Inverza 1.6.3 the moon in AR Sky and the 3D Diorama is drawn at its true apparent size for any date. Frequency: 2 to 5 solar eclipses per year somewhere on Earth, but the shadow track is only a few hundred kilometres wide, so any single spot waits ~375 years on average for a totality. Eclipse photography is travel photography. Photography: certified eclipse glasses and a solar filter for every partial phase; filter off only during totality of a total eclipse. Creative key: sun altitude. Low-horizon eclipses sit inside a landscape (telephoto compression against ridgelines, monuments, the sea), which is what made the 12 August 2026 totality (evening sun ~10 degrees over the Atlantic, Iceland and northern Spain) so photogenic. Totality settings: tripod, bracket 1/1000 s (inner corona) to 0.5 s (outer streamers). Planning with Inverza: every eclipse through 2030 is built in with official NASA/GSFC (Espenak) Besselian eclipse geometry. In the 3D Diorama, scrub time to the eclipse: sun and moon travel their real arcs over real 3D terrain and an eclipse percentage appears when the discs overlap (100% = totality at that exact spot). On location, AR Sky draws the paths on the live camera feed for tripod-level positioning. Spot guide (all with coordinates, mid-eclipse local time, UT, sun altitude, compass direction, central duration): 2027-02-06 annular - Viedma, Argentina (40.810 S, 63.000 W, ring 12:14 local, sun 60 deg, NE, 6m53s) and Mar del Plata (38.000 S, 57.550 W, 12:29 local, 66 deg, NNE, 7m23s). 2027-08-02 total - Luxor, Egypt (25.699 N, 32.639 E, 13:06 local, sun 82 deg, SSW; longest totality on land this century, 6m20s), Tangier, Morocco (35.770 N, 5.800 W, 09:47 local, 38 deg, E, 4m51s), Tarifa, Spain (36.014 N, 5.606 W, 10:48 local, 38 deg, E, 4m40s), Chefchaouen, Morocco (35.169 N, 5.269 W, 09:48 local, 39 deg, E, 4m12s), Cadiz, Spain (36.530 N, 6.290 W, 10:47 local, 38 deg, E, 2m57s). The Strait of Gibraltar cluster at sun ~38 deg is the lowest-sun totality on land for this eclipse (the track starts at sunrise in the open Atlantic; the Azores get only a ~91% partial). 2028-01-26 annular at sunset - Cadiz (17:56 local, sun 8 deg over the sea, WSW, 6m26s), Seville (37.390 N, 5.990 W, 17:56 local, 7 deg, WSW, 7m13s), Galapagos (0.740 S, 90.300 W, 07:25 local, 17 deg, ESE, 5m15s). 2028-07-22 total - Sydney Opera House (33.857 S, 151.215 E, 14:02 local, sun 29 deg, NNW, 3m40s), Queenstown, New Zealand (45.030 S, 168.660 E, 16:17 local, 10 deg, NW, 2m53s). 2030-06-01 annular - Athens (37.980 N, 23.730 E, 07:58 local, sun 20 deg, ENE, 3m46s). 2030-11-25 total - Windhoek, Namibia (22.570 S, 17.080 E, 07:20 local, 17 deg, ESE, 1m38s), Durban, South Africa (29.860 S, 31.030 E, 07:35 local, 34 deg, E, 2m33s). Eclipse predictions by Fred Espenak, NASA's GSFC. --- # Technical stack - Platform: iOS (iPhone), Swift/SwiftUI. - Weather data: Open-Meteo with auto-selected regional models (HRRR, ICON-D2, ICON-EU, ECMWF IFS, GFS), Open-Meteo Marine (sea-surface temperature), Open-Meteo Air Quality (AOD, PM10, Saharan dust), Open-Meteo Previous-Runs (forecast stability), NOAA AWC METAR (airport ground observations), NOAA SWPC (Kp index for aurora). Directional horizon sampling along the sun's azimuth: 40 km near, 150 km twilight, plus 300/450 km far-path ray probes whose cloud layers are gated by the grazing ray's height (August 2026). - Elevation data: NASA SRTM, Open-Meteo Elevation API. - Pressure-level data: 700 hPa and 500 hPa wind, temperature, humidity, geopotential height (used by lenticular cloud detection and upper-air reasoning). - Rendering: Apple Metal compute kernels for GPU-accelerated terrain shadow projection; vector polygon overlays for crisp 2D and 3D shadow rendering at any camera pitch (up to 85 degrees). - AR: ARKit world tracking anchors the AR Sky view's sun, moon, and Milky Way paths to the live camera feed; astronomical positions are computed on device, with a manual compass-calibration control for magnetometer drift. Charts: Swift Charts powers the interactive 7-day raw-data charts (pinch zoom, condition markers, adaptive day/golden-hour/night shading). - Astronomy: sun and moon positions from Meeus-series algorithms computed on device, with topocentric parallax applied to the moon and the lunar distance driving its true apparent size. Solar eclipses use bundled official NASA/GSFC Besselian elements for every central eclipse through 2030 (eclipse predictions by Fred Espenak, NASA's GSFC), evaluated on the observer's fundamental plane for exact obscuration. - AI providers: Anthropic Claude, Google Gemini, OpenAI ChatGPT, and a built-in model (Google's newest Gemini generation; currently Gemini 3.8 Flash). - Locations: Saved locations stored on device; no account required. Multi-location alerts track several spots under a single notification rule.