skylight.

UAL949 United

LHR → SFO

· 2:40Quality 91side-onturned left 17°

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
94%
First lockfrom target selected
5.8 s
Centring, medianaz / el while locked
0.10° / 0.10°
Centring, 90th pctaz / el while locked
0.25° / 0.39°
Tightest field of viewhorizontal
3.4°
Time to 8°from first lock
3.8 s
Time to tightestfrom first lock
108.9 s
Time at telefield of view ≤ 5.5°
136.7 s
Jitter at teleaz / el, standard deviation
0.15° / 0.20°
Swing at teleaz / el, peak to peak
1.44° / 2.17°
Pan reversalsper 10 s at tele
0.4
Largest pan hopin any 1 s at tele
1.78°
Largest tilt hopin any 1 s at tele
0.79°
Pose error, mediancommand vs camera
0.52°
Largest correctionvision vs prediction
0.45°
Zoom steps
34

Aircraft & route

Flight
UAL949
Registration
—
Type
—
Airline
United
From
LHR · London
To
SFO · San Francisco
Ground speed
258 kt
Altitude at closest
11,475 ft
Vertical rate
—
Category
A5
ICAO hex
ab0faa

Pass geometry

Max elevation
30.8°
Elevation at start → end
19.7° → 14.3°
Azimuth at start → end
328° NNW → 85° E
Closest-approach azimuth
20° NNE
Minimum slant range
6.8 km
Heading at closest
110° ESE
Aspect at closest
side-on (90°)
Turn
turned left 17°
Departure
No
Zenith pass
No
Dead-zone wrap
No
Duration
2:40 (160.1 s)
Lock
94%

Build & tuning

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

Build
2026-10-15s — bias fold follows a ramp; no pass below the skyline
Commit
cdd2256
Node
v22.22.2
Camera
TONGVEO 20x PTZ · 1920×1080 @ 30 fps
Clip
79.8 MB · 160.0 s · offset -0.7 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
sigmaGrowthDps
0.1
aimLeadSec
-0.16
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