skylight.

UAL751 United

Boeing 737NG 924ER/W · N39423 · SFO → ?

· 0:18Quality 4no planelost lockwrap pinnednose/tailturned left 33°Dead-zone wrap

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
0%
First lockfrom target selected
—
Centring, medianaz / el while locked
—
Centring, 90th pctaz / el while locked
—
Tightest field of viewhorizontal
8.3°
Time to 8°from first lock
—
Time to tightestfrom first lock
—
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
9.63°
Largest correctionvision vs prediction
0.99°
Zoom steps
40

Aircraft & route

Flight
UAL751
Registration
N39423
Type
Boeing 737NG 924ER/W
Airline
United
From
SFO
To
—
Ground speed
298 kt
Altitude at closest
11,250 ft
Vertical rate
+960 ft/min
Category
A3
ICAO hex
a4945f

Pass geometry

Max elevation
12.3°
Elevation at start → end
12.3° → 11.3°
Azimuth at start → end
180° S → 173° S
Closest-approach azimuth
180° S
Minimum slant range
16.1 km
Heading at closest
155° SSE
Aspect at closest
nose/tail (24°)
Turn
turned left 33°
Departure
Yes — climbing out after take-off
Zenith pass
No
Dead-zone wrap
Yes — pan pre-positioned across the stop
Duration
0:18 (17.6 s)
Lock
0%

Build & tuning

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

Build
2026-10-16g — A/B lockFirst (mount prior on)
Commit
9bdc356
Node
v22.22.2
Camera
TONGVEO 20x PTZ · 1920×1080 @ 30 fps
Clip
9.0 MB · 18.0 s · offset -1.5 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
-0.11
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