Flaring Keyhole USA 129

There was cirrus in the sky in daytime, persisting after sunset. Only after 9 pm local time, the sky had cleared enough from haze to attempt photography. This left only one target, USA 129 (96-072A, #24680), a Keyhole imaging satellite.

It made a zenith-pass near 20:21 UTC during which it put on a spectacular show.

As it cleared the edge of the roof and came into my view in the zenith, it was very bright and clearly flaring. It must have been around mag. 0 to -1, peaking near or before 20:21:20 UTC. When my camera opened it was already past peak brightness for several seconds but still bright, gradualy fading. The image is below.

Obtained two positions from the image. My timings suggest it was 1.15s early with regard to elset 07066.85705303

(click image to enlarge)