USAEARENDIL-1 Passes
Over Chicago
Predicted pass geometry, viewing conditions, and beam footprint data for Chicago when EARENDIL-1 — the first commercial orbital mirror — launches later in 2026. From 41.9°N on the shore of Lake Michigan, EARENDIL-1 can pass directly overhead: an 88° orbit crosses every populated latitude, so the ceiling is the zenith rather than a fixed angle. What differs is how often — at 41.9° N, Chicago gets them regularly, though less often than cities nearer the poles. Passes rise in the SW and transit toward the NE. Chicago's flat prairie geography and eastern lake horizon give exceptionally unobstructed views of pass trajectories.
Predicted geometry for the planned 88° near-polar orbit at 625 km. Eärendil-1 has not launched, so these are modelled figures, not observations — and because the orbit is not sun-synchronous, pass times drift through the year rather than recurring at a fixed hour.
Best: OCT–MAR. Northern winter — long dark nights and the most reliable clear spells.
Seasonal guidance only — based on this location’s latitude and climate, not on Eärendil-1 observations. The mirror has not launched, and because its orbit is not sun-synchronous the pass times themselves drift through the year independently of the weather.
What to Expect in Chicago
What EARENDIL-1 Will Look Like from Chicago
From Chicago, EARENDIL-1 passes will appear as a fast-moving point of light crossing the sky in approximately 3–4 minutes. At peak brightness it will reach magnitude −4 — comparable to Venus at maximum and clearly visible even from the Loop. It will be one of the brightest objects in the Chicago sky during a pass, particularly striking against the Lake Michigan horizon to the east.
The mirror is steerable — between targeted commercial passes, Reflect Orbital tilts it away from Earth, making it much dimmer or invisible. During an active commercial pass you'll see a sudden brightening as the beam angle locks onto the target region. The pass ends abruptly when the mirror tilts away again.
Unlike a steady satellite, EARENDIL-1 may show subtle brightness variations as the mirror adjusts its aim. Watch for a brief period of maximum brightness near the peak of the pass when the geometry is optimal — this is when the 5km ground footprint is directly beneath the mirror at closest approach.
Track EARENDIL-1 from Chicago at Launch
OrbitalNodes.ai will provide real-time pass predictions for Chicago from the moment EARENDIL-1's orbital data is published. No app download required — runs entirely in your browser with GPS-accurate directions.
◈ OPEN ORBITALNODES.AISpace Mirror Questions — Chicago
How bright will EARENDIL-1 appear from Chicago?
At peak overhead passes, EARENDIL-1 is designed to reach magnitude −4 — comparable to Venus at maximum brightness. This is easily visible from the lakefront, Navy Pier, the Willis Tower Skydeck, or anywhere in the Loop despite Chicago's significant urban light pollution (Bortle 8). Between commercial illumination passes, Reflect Orbital tilts the mirror away from Earth, reducing brightness significantly.
How high will EARENDIL-1 appear from Chicago?
From 41.9°N in the US Midwest, EARENDIL-1 can pass directly overhead: an 88° orbit crosses every populated latitude, so the ceiling is the zenith rather than a fixed angle. What differs is how often — at 41.9° N, Chicago gets them regularly, though less often than cities nearer the poles. Passes rise in the SW and transit toward the NE — the standard direction for northern-hemisphere observers of near-polar satellites. Higher elevation passes give a longer viewing window and brighter appearance. Chicago's latitude is similar to Madrid, Rome, and Beijing.
When is the best time to see it from Chicago?
September through October offers Chicago's most reliable viewing — clear skies following frontal passages, mild temperatures, and minimal humidity. Winter (December–February) can produce exceptional clarity after Arctic air masses, though temperatures often drop below −20°C. Summer is humid with frequent afternoon thunderstorms that often clear by evening. Spring is variable with rapidly changing weather fronts.
Will the beam footprint hit Chicago?
A 5km beam footprint could span from Navy Pier to the Willis Tower and onto Greektown in a single pass — covering virtually the entire downtown core. Alternatively, a beam targeting the lakefront could illuminate Millennium Park, Grant Park, and the Museum Campus simultaneously. A pass aimed at the Lincoln Park neighborhood could cover from Diversey Harbor to North Avenue Beach. Whether any specific location falls in the footprint depends on Reflect Orbital's commercial contracts and targeting decisions. The beam is steerable and can be directed to specific cities or regions for commercial lighting purposes.
Is EARENDIL-1 visible yet?
No — EARENDIL-1 has not launched yet. Reflect Orbital is targeting a launch later in 2026. There is currently no space mirror in Earth orbit. OrbitalSolar.ai will update with live pass data from the moment orbital elements are published after launch. Check the mission tracker for current launch status.
Why does the mirror move differently from Chicago than from other cities?
From the Northern Hemisphere at 41.9°N, EARENDIL-1 rises in the SW and transits NE — the standard direction for northern observers of near-polar satellites. Southern Hemisphere observers in Sydney, Melbourne, or Cape Town see the mirror image of this pass, with the satellite rising in the NW and transiting NE. This is because near-polar satellites cross close to the poles, tracking the boundary between Earth's day and night sides.
How does Chicago's flat terrain and Lake Michigan shoreline interact with the 5km beam?
Chicago is built on a former glacial lakebed — the terrain is among the flattest of any major city, giving unobstructed views to every horizon. Lake Michigan stretches east for hundreds of kilometers, providing a completely dark seaward horizon free of any land-based light pollution. A 5km beam footprint could cover the entire downtown core from Navy Pier to Greektown, or alternatively illuminate the lakefront from Millennium Park to Museum Campus with the lake as a dramatic reflective backdrop. Chicago's geography makes it visually distinctive for orbital mirror demonstrations — the combination of dense vertical skyline and vast flat water creates unique beam-illumination imagery.
What dark-sky locations near Chicago are best for watching the mirror pass?
The Blue Mountains (90 minutes west, Bortle 3–4) give the clearest sky with minimal light dome interference. Ku-ring-gai Chase National Park (45 minutes north) is excellent for clear northern passes. Royal National Park (45 minutes south) has a clear southern horizon. For serious observation, Observatory Hill in the CBD works for the bright mirror itself — at magnitude −4 it needs no dark sky — but the Blue Mountains are far better for seeing the beam footprint effect against a dark sky backdrop.
OrbitalNodes.ai tracks the ISS, Tiangong, Hubble, and all satellites over Chicago in real time — including exact pass times, directions, and brightness predictions.
→ SATELLITES OVER CHICAGO — ORBITALNODES.AI