The Seattle Astronomical Society was holding a viewing at the time. There were several experts there who saw it who might be able to give a better report.
Location
Address
Shoreline, WA
Latitude
47° 44' 25.58'' N (47.74044°)
Longitude
122° 19' 12.22'' W (-122.32006°)
Elevation
122.159m
Time and Duration
Local Date & Time
2017-07-29 22:00 PDT
UT Date & Time
2017-07-30 05:00 UT
Duration
≈7.5s
Direction
Moving direction
From up right to down left
Descent Angle
268°
Moving
Facing azimuth
89.99°
First azimuth
104.62°
First elevation
40°
Last azimuth
16.32°
Last elevation
26°
Brightness and color
Stellar Magnitude
-13
Color
Light Blue, Light Green, Red
Concurrent Sound
Observation
No
Remarks
-
Delayed Sound
Observation
Unknown
Remarks
Like rolling thunder many minutes after from the direction I last saw it
