Friday, 31 July 2009

Flaring Keyhole USA 161

Yesterday evening/early night was a night with intermittent very clear skies, and large cumulus fields roving the skies. I was lucky though with the selected targets, although some narrowly escaped the roving cloud fields only. I observed 3 Keyholes (USA 129, USA 161 and USA 186) and Lacrosse 3.

USA 129 (96-072A) was imaged low in the sky in a small gap between clouds. USA 186 (05-042A) was imaged in twilight and the trails were rather faint. It briefly flared to mag. -1, before the camera was open, at roughly 22:59:50 UTC.

USA 161 ((01-044A, a Keyhole high-resolution optical reconnaissance satellite, like the other two USA objects mentioned) also briefly flared to -1 a few times. It did so twice while the camera was open, at 23:28:13.40 UTC and 23:30:17.15 UTC, resulting in the pictures below:

(click images to enlarge)

The second image yielded this brightness profile, with the flare saturating at the peak:

(click diagram to enlarge)

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