EPIC Projector.Earth — User guide
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. Menu → Help shows the same globe gestures, plus extra help for whichever extension is on, with links here and to that extension’s guide.
Contents
- Open the app
- What’s on screen
- Globe gestures
- Timeline
- Keyboard (desktop)
- Views
- Menu
- Settings
- Extensions
- Share
- Tips
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. Playback starts on by default. |
| Latest | Skip-to-end icon (`-> |
| View info | Captions opposite the menu (DSCOVR, L1, GEO, Moon, zoom). Hide or show from Settings or the caption itself. |
| Menu | Corner button (right by default): Sign in, Share, Extensions, Settings, Help, About. |
| Analemma | Up-triangle opposite the date when a weather event is selected (Macro weather). Preloads that event’s days; tap when it pulses to play them. See Macro weather. |
| Timeline | Bottom strip (portrait) or side strip opposite the menu (landscape). Red arrow = current time. Long-press, then drag to widen/narrow the visible time window. Does not scrub time. |
After 5 seconds with no input, chrome (menu, time bar, timeline, 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.
| 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. |
| 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 stays at the centroid you chose. Long-press first to scrub time instead. Zoomed → scrub time. | Scrub EPIC time (snaps on release). Long-press first for GEO orbit instead. |
| Long-press | Unzoomed → time scrub (inverse of pause). Zoomed → grab-pan. | Unzoomed → GEO orbit. Zoomed → grab-pan. |
| Swipe up | Pause and jump to the latest EPIC day at now. | Latest EPIC day at the current time of day. |
| Swipe down | If Analemma is showing, same as the up-triangle. | Analemma if showing; otherwise jump back one day. |
| Double-click | Pause (no snap). In GEO or L1, return to the EPIC Earth. Otherwise toggle zoom at that point. | 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.
Timeline
The timeline shows your place in the EPIC archive and the width of the visible time window.
| Portrait | Horizontal strip at the bottom; time bar sits above it |
| Landscape | Vertical strip on the side opposite the menu |
| Red arrow | Current time, always centered |
| Labels | Adapt to scope: hours, days, months, or years |
| Blue marks | Individual EPIC frames when zoomed in; when dots would overlap, a cadence stairs graph (light blue fill from the track to the curve) |
| Cadence peaks | Steps above the usual ~20 frames/day baseline are selectable — hover highlights; click selects the burst (1 h/s play, scoped timeline). Tap the event name above the date to leave |
| Pink day brackets | While Love is on: UTC days with watchers (emoji grid). Tap → play that day at 1 h/s from 00:00 UTC, without changing zoom. |
Change the time window (scope)
- Long-press the timeline (~half a second).
- Watch the brief ×10 → ÷10 → ×1 pulse — that teaches scope change.
- Drag along the scope axis:
- Portrait: drag right to widen, left to narrow.
- Landscape: drag up to widen, down to narrow.
Range is limited from 24 hours to about 10 years of EPIC data. Your last scope is remembered.
The timeline does not scrub time. Scrub on the globe; play, pause, and the date label work as before.
Cadence graph (zoomed out)
When individual EPIC dots would crowd together, the strip switches to a stairs graph of local cadence: at each interior frame, height reflects 86400 / (t[i+1] − t[i−1]) images per day (normalized so ~20/day is the reference level). Long gaps are holes; short sustained runs are peaks (eclipse days, calibration campaigns, etc.).
- The area from the timeline mainline up to the curve is filled with light transparent blue.
- Hover a peak above baseline for a brighter highlight.
- Click a peak to select that high-cadence interval: clock and scrub clamp to the burst, timeline zooms in, playback runs at 1 h/s for smooth frame interpolation. Click the same peak again, or tap the caption above the date, to leave.
- Hit targets stay at least 20 px wide/tall so thin peaks remain clickable when zoomed out.
This uses the same playback window machinery as a selected Macro weather card (controlState.macroWeather, category epic_cadence) — no Macro weather extension required.
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 (zoom), or the menu.
| View | What you see |
|---|---|
| DSCOVR | Whole Earth from DSCOVR 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 on extra limbs. 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. |
| 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. |
Menu
| Item | Action |
|---|---|
| Sign in / Sign out | Always in the main menu. Google identity (openid). The session is remembered. Sky photos asks for Drive later, the first time you publish or open your Drive folder. Love does not use this account. |
| Share | Share a link to the current time, view, and active extension (plus extra data some extensions add). |
| 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). Long-press the icon to switch extensions. |
| 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 in the panel | 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. 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 captions. Off when opening a shared link. |
| Extended UI | On (desktop) / off (phone) | Extension panels: filters, strips, Love HUD, Sky Photos camera button. 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 closest real frame when paused. Prefetch and analemma 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 + recent ATCF tips), solar eclipses (NASA paths + umbra), and wildfires (NASA FIRMS / clustered VIIRS hotspots). Globe gestures still work on Earth.
Storms and eclipses can be opened from the globe even when Macro weather is off or Love / Sky photos is on — click picks the event, turns Macro weather on (chips off), and zooms. Wildfires are strip/timeline only. Desktop hover shows a short label on pickable storms and eclipses.
High-cadence EPIC bursts are no longer a Macro weather category. When the timeline is zoomed out, use the cadence stairs graph on the EPIC strip to find and select bursts (see Timeline → Cadence graph).
Selecting a card (or a globe pick) zoom-pivots when the event has a location, keeps the clock in UTC, and shows Analemma for that event’s days. Intensity chips start off; turning chips on while selected adds overlays without unselecting. Back or zoom out after a globe pick from another extension restores that extension. Turning Macro weather off from the menu keeps the current zoom pivot.
| Control | Action |
|---|---|
| Click storm / eclipse on globe | Select event (works with Macro weather off). |
| Event type | Storms / Eclipses / Wildfires |
| Intensity chips | Storms: C5…TD. Eclipses: Tot / Ann / Hyb / Par. Wildfires: Giga / Mega / XL / L / M. All off by default. |
| Search | Filter the strip by name. Typing search temporarily disables the chips. |
| Click a card | Jump the globe to that event’s time. Click again to leave. |
| Back | Previous pick in session, or exit globe pick and restore prior extension. |
Sky photos
Photos of the sky from the ground, on Earth and in a day strip. Playback pauses while this extension is on.
Sign in (main menu) identifies you. The first time you publish or open Drive folder (under Sky photos in Extensions), Google asks for Drive so the files stay in your Drive.
| Control | Action |
|---|---|
| Drag strip | Scroll photos horizontally. |
| Click card | Jump to that photo’s time. |
| Click thumb | Open the photo popup on the globe. |
| Camera | Corner camera button under the extension toggle. Takes a photo (Drive on first publish). |
| Drive folder | Open your Sky photos folder in Google Drive. |
Love
Send an emoji arc from one place on Earth to another. Location is optional. Love uses anonymous presence, not the Google Sign in row.
- 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. While Love is on, playback runs at 10 min/s and does not snap to EPIC frames. 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.
- Your watching day (UTC day of the EPIC clock) is written with presence; while Love is on, pink day brackets on the timeline show who is watching where.
- Turning Love off (or leaving the page) clears your presence and cloud sends.
Share
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. Recipients open the same moment on Earth. A parked GEO tilt includes view=geo:lat,lon 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.
- 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
