skylight.

UAL990 United

Boeing 777 224ER · N78017 · SFO → CDG

· 1:13Quality 74lost locknose/tail

3D replay

Software-steadied: the hops of the camera motor are smoothed out (plane wobble −57%). Download

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
63%
First lockfrom target selected
22.1 s
Centring, medianaz / el while locked
0.36° / 0.43°
Centring, 90th pctaz / el while locked
5.01° / 2.61°
Tightest field of viewhorizontal
5.0°
Time to 8°from first lock
35.8 s
Time to tightestfrom first lock
45.7 s
Time at telefield of view ≤ 5.5°
4.8 s
Jitter at teleaz / el, standard deviation
—
Swing at teleaz / el, peak to peak
—
Pan reversalsper 10 s at tele
6.3
Largest pan hopin any 1 s at tele
0.86°
Largest tilt hopin any 1 s at tele
0.52°
Pose error, mediancommand vs camera
0.91°
Largest correctionvision vs prediction
2.81°
Zoom steps
60

Aircraft & route

Flight
UAL990
Registration
N78017
Type
Boeing 777 224ER (B772)
Airline
United
From
SFO · San Francisco
To
CDG · Paris
Ground speed
185 kt
Altitude at closest
1,300 ft
Vertical rate
+2,432 ft/min
Category
A5
ICAO hex
aa9321

Pass geometry

Max elevation
81.6°
Elevation at start → end
0.1° → 11.9°
Azimuth at start → end
116° ESE → 299° WNW
Closest-approach azimuth
27° NNE
Minimum slant range
433 m
Heading at closest
298° WNW
Aspect at closest
nose/tail (7°)
Turn
straight (0°)
Departure
Yes — climbing out after take-off
Zenith pass
No
Dead-zone wrap
No
Duration
1:13 (73.1 s)
Lock
63%

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
36.5 MB · 73.0 s · offset -1.0 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
-0.21
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