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. 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
• Movie Clip
• Timeline
• Keyboard (desktop)
• Views
• Menu
• Settings
• Extensions
  • Weather
  • Skypics
  • Presence
• 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.

With no share / query params, the app opens in DSCOVR view at the latest EPIC day. J2000 and Ecliptic orientation are remembered; DSCOVR spacecraft attitude is not. A share link still opens the linked view, time, and selection.

What’s on screen

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.

Speed steps: 1s/s, 1min/s, 5min/s, 10min/s, 20min/s, 30min/s, 1h/s (default), 2h/s, 6h/s, 1d/s, 1w/s, 1mo/s.

Movie Clip

Menu → Movie Clip (under Share) is a super-user feature for now: you must be signed in as the super user. It opens one dialog with one zone at a time:

1. Recipe — current date and time (UTC pickers), plus menus for speed, position, orientation (DSCOVR / L1), exclusive extension (None or one), and range (Last / Next / Current cycle, or till the last EPIC image). Each control starts at the live value. The cycle word follows the recipe speed (day, week, month, year). Start bakes in the background. Check Notify me when the movie is ready for an OS banner if you switch away.
2. Baking — progress, the date of the last encoded frame, download-so-far, or Cancel. The globe stays usable; hiding the tab does not pause the bake.
3. Ready — Download, Share, New (confirm, then back to the recipe), or Drop (confirm, discard the file, and close the dialog). Close and reopen while a file is still in memory and you are on Ready again. Cancel while baking also asks first.

The Movie Clip menu item gets an orange underline while baking and a green one when a clip is ready. Closing or reloading the page drops the bake and the finished file. If this browser cannot encode H.264, Start is disabled. Days NASA skipped keep the last Earth and still step the date stamp. Share attaches that MP4 when it is in memory.

Timeline

The timeline shows your place in the EPIC archive and the width of the visible time window.

Change the time window (scope)

1. Long-press the timeline (~half a second).
2. Watch the brief ×10 → ÷10 → ×1 pulse — that teaches scope change.
3. 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 / frequency line

When EPIC frames would crowd on the strip, marks coalesce and same-cadence runs become a frequency line on the track (same width as the dots). Cadence is binned to about 10 (dark blue) or 20 (light blue) images/day so neighboring dots merge into plateaus; empty stretches stay as holes. Spaced frames stay as individual dots — only overlapping clusters become line.

Selectable high-cadence bursts (roughly ≥2 frames per hour across more than three hours) stay white, with a larger hit target (~5× the visible radius): spaced frames as white dots; when they overlap, a white selectable line across the burst:

• Hover a white burst for its span label.
• Click to select that interval: clock and scrub clamp to the burst, timeline zooms in, playback runs at 1 h/s for smooth frame interpolation. Click the same burst again, scrub far past it, or tap the caption above the date to leave.

This uses the same playback window machinery as a selected Weather card (controlState.playbackWindow, category epic_cadence) — no Weather extension required.

Keyboard (desktop)

Shown in Help on mouse/trackpad devices.

Views

Use the camera view dropdown, double-click (zoom), or the menu.

Menu

Settings

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: Weather · Skypics · Presence

Weather

Storms (IBTrACS + recent ATCF tips; European extratropical via Copernicus EWS / curated EUMETNET names; North American extra-tropical via ERA5 ETC, including nor'easters), solar eclipses (NASA paths + umbra), and smoke (NOAA HMS Heavy + CAMS NRT organic-matter AOD worldwide, with FIRMS megafire enrichment). Globe gestures still work on Earth.

Storms, eclipses, and smoke plumes can be opened from the globe even when Weather is off or Presence / Skypics is on — click selects the event and zooms without turning Weather on (no filter/chips/strip). The storm stays on the globe and timeline while Weather remains off. Wildfires only appear while Weather is on (flames always; name labels on hover or when selected). Desktop hover shows a short label on pickable targets.

High-cadence EPIC bursts are no longer a Weather category. Use the white marks on the EPIC strip to find and select bursts (see Timeline → Cadence / frequency line).

Selecting a card (or a globe pick) zoom-pivots when the event has a location, keeps the clock in UTC, and shows Analemma for multi-day events (eclipses play at ~1 min/s instead). A selected named storm, solar eclipse, smoke plume, or wildfire may also show a short Wikipedia summary under the globe name (year+place season pages for smoke/fire). Other storms, eclipses, smoke plumes, and wildfires are hidden on the globe and timeline while an event is selected, but stay hover/click pickable on the globe. Intensity chips are all on when Weather is turned on and filter both the globe overlays and the timeline; events whose chip is off are hidden but still hover/click pickable. The filter bar shows only while Weather is on and no event is selected (unselect with Back / Escape to get it back). It sits beside the extension toggle: category / search / None·All on one row, chips underneath (swipe on a narrow phone). Search shows matching cards; click a card to select it and jump to the storm’s peak date (or the eclipse). Back / Forth (beside the menu) steps any prior selection — storms, eclipses, smoke, wildfires, cadence bursts, sky photos — or returns to unselected. Android Back and desktop Escape do the same. Turning Weather off from the menu keeps the current selection (overlay + timeline) and zoom pivot.

Skypics

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 Skypics in Extensions), Google asks for Drive so the files stay in your Drive.

Presence

Send an emoji arc from one place on Earth to another. Location is optional. Presence 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 Presence toggle (direction into the globe). Tap the eye to pick an emoji.
• Aiming pauses playback; sending resumes it. While Presence 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 Presence 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 Presence is on, pink day brackets on the timeline show who is watching where.
• Turning Presence off (or leaving the page) clears your presence and cloud sends.

Share

Share sends a link with the current day, time, view, speed, and active extension, plus a file when the browser allows it: the Movie Clip MP4 when one is ready, otherwise a screenshot of the globe. Download and Share are also on the Movie Clip Ready zone. 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. Elastic GEO tilt is a personal setting (not in the share link). 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. It also leaves a selected weather event or cadence burst.
• 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.
• True Color (the aperture button under the menu, also in Settings) is on by default: you only see real NASA EPIC photographs of the Earth. Time stays within EPIC coverage, missing days are jumped over, and playback stops on the latest EPIC image. Turn it off to go past the latest image and over gaps on Blue Marble with satellite clouds, up to the real now.
• With True Color off, past the latest EPIC image, Blue Marble gets satellite clouds: the live map at the real now (Latest twice), and the 3-hourly map nearest the shown time before that (e.g. a sky photo taken there). Cloud maps: Live Cloud Maps by Matt Eason (contains modified EUMETSAT data), with past frames from joshuabinswanger's archive.
• Contact: info@projector.earth