EPIC Projector.Earth — User guide
Live app Interactive 3D Earth from NASA’s EPIC camera on DSCOVR (Lagrange point L1). Playback interpolates between hourly frames so clouds and lighting move continuously.
This guide is for people using the app. The in-app Help panel (menu → Help) shows the same gestures, plus extra help for whichever extension is on, with links to this guide and the active extension’s guide.
Open the app
Use a modern browser over HTTPS (or http://localhost when running locally). You can install it as a PWA from the browser’s install prompt.
EPIC data usually lags a few days. Until frames load, the globe shows Blue Marble imagery.
What’s on screen
| Area | What it does |
|---|---|
| Globe | Whole-Earth view from the Sun’s line of sight (DSCOVR). Click to play/pause (a brief center icon confirms). |
| Date / time | Current EPIC date, time, and (UTC) / (Local) on one line. Tap it to pick a date. |
| Play button | Above the date, next to the speed — play or pause. Playback starts on by default. |
| Analemma | An up-triangle on the opposite bottom corner from the date, shown as soon as you pause. Analemma means animation for same time of day everyday. When a multi-days event is selected, those days will be preloaded and the analemma animation will be limited by it. Without selection, animation covers a full year until current EPIC day. Preloading starts upon first button press. A second tap will start the animation from the oldest day preloaded. |
| Latest | Skip-to-end icon (`-> |
| View info | Captions opposite the menu (DSCOVR, GEO, Moon, zoom, map). Hide or show from Settings or the caption itself. |
| Menu | Corner button (right by default): Share, views, Extensions, Settings, Help, About. Sky photos adds Sign in. |
After 5 seconds with no input, chrome (menu, time bar, filters, HUD) fades. Move or touch to bring it back. Globe overlays stay. Toggle this in Settings.
Globe gestures
Behavior depends on whether playback is running and whether you are zoomed or in map view.
| Gesture | While playing | While paused |
|---|---|---|
| Click | Play / pause | Play / pause |
| Drag up / down | Step playback speed (1s/s … 6h/s). A toast shows the new rate. | Jump forward or back one day at the same time of day. After a short pause it snaps to the nearest EPIC frame (clean still). The analemma control is already opposite the date (pause shows it). |
| Drag left / right | Unzoomed globe → GEO longitude (play keeps running). From DSCOVR, springs back to EPIC unless Elastic GEO tilt is off or you hold Shift. GEOSTAT view stays at the centroid you chose. Long-press first to scrub time instead. Zoomed or map → scrub time. | Scrub EPIC time (snaps on release). Long-press first for GEO orbit instead. Changing the time of day resets the year analemma to the new hour (and restarts event-window preload if a weather event is still selected). |
| Long-press | Unzoomed → time scrub (inverse of pause). Zoomed → grab-pan. Map → zoom + scrub. | Unzoomed → GEO orbit. Zoomed → grab-pan. Map → zoom + scrub. |
| Swipe up / down | Jump to latest day (up) | Up: latest EPIC day at the current time of day (resets analemma to that hour). Down: same as the up-triangle — prepare a year of this hour, then play-through from the oldest loaded same-TOD day (press again or swipe down to stop and return). |
| Double-click | Pause (no snap) and cycle zoom / map views. In GEO, returns to the EPIC Earth. | Same |
| Pinch / mouse wheel | Zoom in or out | Same |
| Tap the date | Open the date picker | Same |
Speed steps: 1s/s, 1min/s, 5min/s, 10min/s, 20min/s, 30min/s, 1h/s (default), 2h/s, 6h/s.
Keyboard (desktop)
Shown in Help on mouse/trackpad devices.
| Key | Action |
|---|---|
| Space | Play or pause |
| ↑ / ↓ | Jump forward or back one day |
| ← / → | Previous or next EPIC frame |
| Shift + drag left / right | GEO tilt: park at the current longitude (does not change the Elastic GEO tilt setting). |
| M | Toggle Moon view |
| E | Cycle the last selected extension (panels → overlay only → off). Double-click the corner icon to hide it. |
Views
Use the camera view dropdown, double-click cycling, or the menu.
| View | What you see |
|---|---|
| DSCOVR | Whole Earth from the DSCOVR satellite in a halo orbit around L1 (~1.5 million km). Hourly NASA EPIC frames with interpolation between them. |
| L1 | Exact Sun–Earth L1, on the line of the Sun. DSCOVR is offset around L1, so this recenters the subsolar point. Night side, stars, and Sun are simulated. Share with view=l1. |
| GEOSTAT (GEO) | Looking from ~36,000 km above the equator. Drag left/right while playing to change longitude (and latitude after a clear horizontal scrub). The view stays at the centroid you chose. Elastic spring-back to EPIC applies again when you switch to another view. Double-click also returns to EPIC. Night side, stars, and Sun are simulated. |
| Moon | Earth as seen from the Moon (Earthrise-style, Moon at the bottom of the frame). Phases are opposite: new Moon is full Earth. Toggle with M or the views menu. |
| Zoom / pivot | Double-click a point: zoom on that location. The clock shows the city (or region) when known, in the pivot timezone. Un-zoom returns the clock to UTC. Drag scrubs time so you see cloud motion at the pivot. |
| Map | Flat map (Mercator or equirectangular, depending on window shape). Menu → Map mode when available. Double-click to return to the globe. |
Menu
| Item | Action |
|---|---|
| Share | Share a link to the current time, view, and active extension (plus extra data some extensions add). |
| Sign in / Sign out | Only while Sky photos is on. Google account required to upload; the session is remembered. |
| Map mode | Switch between globe and flat map (when the map feature is enabled). |
| Moon view | Earth-from-Moon camera. |
| Extensions | One overlay at a time: Macro weather, Sky photos, or Love. The corner icon (and E) cycles panels + overlay → overlay only → off. Double-click the icon to hide it (Share then includes extension=none). |
| Settings | Menu side, chrome, extended UI, captions, hints, globe look, EPIC source, image format, speed, cache. |
| Help | Gestures for the globe plus the active extension, and links to the full user guides. |
| About | Version, credits, whitepaper, NASA / Blueturn links, contact. |
Settings
| Setting | Default | Notes |
|---|---|---|
| Menu position | Right | Left or right corner. Captions sit on the opposite side. |
| Zoom circle | On | Visual zoom target. |
| Earth disk clipping | On | Clip drawing to the Earth disk. |
| Day/night blend | 22% | Twilight band softness on the globe. |
| City lights | 12% | Night-side city lights brightness. |
| Elastic GEO tilt | On | From DSCOVR, longitude springs back to EPIC after you release. Off: stay at the tilted longitude (double-click returns). Choosing GEOSTAT in the views menu always parks (elastic returns when you leave that view). Desktop Shift+drag parks without changing this setting. |
| Hide controls when idle (5s) | On | Menu, time, filters, HUD fade; overlays stay. |
| Show view info | On | DSCOVR / L1 / GEO / Moon / map captions. Off when opening a shared link. |
| Extended UI | On (desktop) / off (phone) | Extension panels: filters, strips, Love HUD, Sky Photos FAB. Globe overlays stay. The corner extension button cycles this with on/off. |
| Up/down drag hint | On | Coaching toast for speed (play) or day jump (pause). |
| Analemma play hint | On | Pulse the Analemma play button until you tap it. After the first tap it pulses a few times. Check again to restore the repeating hint on the next weather event. |
| EPIC images source | NASA | NASA, BT-S3, or BT-CDN. Switching clears the image cache. |
| Paused image format | PNG | JPG or PNG for the two images bracketing the current time when paused. Prefetch and analemma play-through stay on JPG. |
| Time speed | 1h/s | Same discrete steps as vertical drag. |
| Clear cache | — | Drop cached EPIC imagery (reload after). |
Your settings stay in this browser. A shared link overrides them so the recipient sees the same moment. Opening a shared link also turns Extended UI and Show view info off so the globe stays the focus.
Extensions
Only one extension is on at a time. Turn them on from Menu → Extensions. In-app Help then adds that extension’s gestures. Double-click the corner extension icon to hide it (same as ?extension=none); Share then keeps extension=none on the link.
Full guides: Macro weather · Sky photos · Love
Macro weather
Storms (IBTrACS), solar eclipses (NASA paths + umbra), wildfires (NASA FIRMS / clustered VIIRS hotspots), and Cadences (exceptional EPIC frame density — eclipses, special NASA campaigns). Cadences has no globe overlay; the strip jumps into the burst window. Globe gestures still work on Earth.
With Macro weather on (no card selected), year analemma play-through holds 5 days/s on C4/C5 storm track days, total eclipse days, and mega / giga fire windows, and otherwise ramps 5→30 when the GPU runway is full (events hidden by intensity chips do not slow). Selecting a card shows Analemma for that event’s days, keeps the clock in UTC, and pulses the play button when those frames are ready (10 days/s).
| Control | Action |
|---|---|
| Event type | Storms / Eclipses / Wildfires / Cadences |
| Intensity chips | Storms: C5…TD. Eclipses: Tot / Ann / Hyb / Par. Wildfires: Mega / XL / L / M. Cadences: no chips — all bursts above ~1 frame/h. |
| Search | Filter the strip by name. Typing search temporarily disables the chips. |
| Drag the strip | Scroll events horizontally (wheel also works). |
| Click a card | Jump the globe to that event’s time. |
Sky photos
Photos of the sky from the ground, on Earth and in a day strip. Playback pauses while this extension is on.
| Control | Action |
|---|---|
| Drag strip | Scroll photos horizontally. |
| Click card | Jump to that photo’s time. |
| Click thumb | Open the photo popup on the globe. |
| + / FAB | Add a photo from camera or gallery (Sign in required; the session is remembered). |
| Sign in | In the main menu while this extension is on. |
Love
Send an emoji arc from one place on Earth to another. Location is optional.
- With GPS: you appear as an eye on Earth. Tap it to pick an emoji; drag from the eye to a visible point and release to send.
- Without GPS: drag from the corner eye under the Love toggle (direction into the globe). Tap the eye to pick an emoji.
- Aiming pauses playback; sending resumes it. Each send is tied to the current EPIC time — share a link so friends meet you on the same moment.
- You see people who are online now (plus your own sends). The HUD shows how many are watching.
- Share while Love is on creates a meet session so joiners highlight each other’s eyes.
- Turning Love off (or leaving the page) clears your presence and cloud sends. Press E or tap the heart under the menu (cycles panels on, overlay only, then off). Double-click the heart to hide the icon.
Share and accounts
Share copies a link with the current day, time, view, speed, and active extension. If you hid the extension icon (double-click, or opened with ?extension=none), the link includes extension=none so the recipient also gets a globe with no extension chrome. Recipients open the same moment on Earth. A parked GEO tilt includes view=geo:lat,lon (omit coords → current EPIC centroid) and elasticTilt=0 when elastic is off. L1 uses view=l1. A shared (deep) link turns off Extended UI and view info so they land on the globe, not the extra panels.
Tips
- Open Help while you learn gestures — it updates when you turn an extension on, and links to this guide (and that extension’s guide).
- Latest is the fast way back to “now” on the newest available EPIC day.
- Vertical drag while playing is the fastest way to change speed; the rate also lives next to play and in Settings.
- Some EPIC days are missing frames; the app interpolates and may show Blue Marble until NASA data arrives.
- Contact: blueturn.earth@gmail.com
