Friday, 28 March 2014

A flare show by USA 245

Wednesday evening saw a dynamic atmosphere, where clear skies intermittently were broken by fields of fast moving scattered clouds.

I targeted all three West plane KH-11 Keyhole/CRYSTAL satellites that evening: USA 129 (1996-072A), USA 186 (2005-042A) and USA 245 (2013-043A).

USA 245 had a pass during a period where patches of clouds occupied the southern sky up to the zenith. The image below shows it rising through Leo, over the roof of my house, amidst scattered clouds:

click image to enlarge

USA 245 twice flared brightly during this pass. Such flares are caused when a reflective surface on the satellite (solar panels, an antenna panel, a dish or some other part of the structure) acting like a mirror reflects sunlight directly towards the observer. I love it when they do that, it is always spectacular.

The first flare was a slow bright one up to magnitude -2 peaking near 20:27:28 UTC (26 March) just above the back of Leo:

click image to enlarge

One-and-a-half minutes later at 20:29:03.64 UTC, while passing through Uma, it flared again, a more brief glint/flare to magnitude -1:

 click images to enlarge

USA 129 was also observed, low in the west while emerging from earth shadow. It only faintly registered on one image, allowing one position determination. USA 186 was not seen, but this was likely due to unfavourable circumstances (it was too faint for the lens used) as Cees Bassa did observe it, on-time, the next day.

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