skylight.

UAL857 United

Boeing 777 300ER · N2737U · SFO → PVG

· 0:53Quality 75nose/tail

3D replay

Trace

Where the aircraft sat in the frame, second by second. Click the chart to jump the video there.

—FOV —az —el —pose —
Lock

Events

Tracking metrics

How well the camera kept the aircraft centred. Tap a metric for what it means and what good looks like.

Lockshare of the pass
56%
First lockfrom target selected
18.8 s
Centring, medianaz / el while locked
0.95° / 0.52°
Centring, 90th pctaz / el while locked
7.87° / 6.37°
Tightest field of viewhorizontal
6.6°
Time to 8°from first lock
31.0 s
Time to tightestfrom first lock
31.3 s
Time at telefield of view ≤ 5.5°
0.0 s
Jitter at teleaz / el, standard deviation
—
Swing at teleaz / el, peak to peak
—
Pan reversalsper 10 s at tele
—
Largest pan hopin any 1 s at tele
—
Largest tilt hopin any 1 s at tele
—
Pose error, mediancommand vs camera
1.10°
Largest correctionvision vs prediction
1.82°
Zoom steps
20

Aircraft & route

Flight
UAL857
Registration
N2737U
Type
Boeing 777 300ER (B77W)
Airline
United
From
SFO · Seoul
To
PVG · Shanghai (Pudong)
Ground speed
201 kt
Altitude at closest
975 ft
Vertical rate
+3,072 ft/min
Category
A5
ICAO hex
a2b501

Pass geometry

Max elevation
82.0°
Elevation at start → end
0.0° → 13.4°
Azimuth at start → end
116° ESE → 299° WNW
Closest-approach azimuth
20° NNE
Minimum slant range
359 m
Heading at closest
297° WNW
Aspect at closest
nose/tail (5°)
Turn
straight (0°)
Departure
Yes — climbing out after take-off
Zenith pass
No
Dead-zone wrap
No
Duration
0:53 (52.6 s)
Lock
56%

Build & tuning

The tracker build that flew this pass and the live settings that mattered, so passes can be compared across changes.

Build
2026-10-14f — camera profile, head-axes control, speed floor, park from profile, learned lead
Commit
181d1fa+wip
Node
v22.22.2
Camera
TONGVEO 20x PTZ · 1920×1080 @ 30 fps
Clip
26.5 MB · 53.0 s · offset -1.4 s
pursuit
velocity
maxLeadSec
3
panLatencySec
0.6
tiltLatencySec
0.4
rippleDeg
0.5
rippleTeleDeg
0.25
maxSpeedStepFwps
0.45
speedReachFrac
0.8
lockedSigmaDeg
0.35
correctionSlewDps
2.5
kp
1
ki
0.6

This clip and poster are © Skylight (Cameron Paczek): free for non-commercial use with credit to skylightceiling.com, not MIT. License