Thursday 27 May 2010

An IGS 1B flare, and Geostationary satellites again

Last evening 25-26 May was not the best of evenings: cirrus, and moonlight, plus this time of the year the sky darkens late and in fact remains in twilight all night at 52 N.

In twilight, I observed the KH-12 KeyHole USA 186 (05-042A), IGS 1B (03-009B), and Lacrosse 4 (00-047A). Short after midnight, the still flaring commercial geostationary satellite Galaxy 11 (99-071A) and the classified military geostationary satellite Milstar 5 (02-001A) were the target.

IGS 1B slowly flared to mag. -0.5 at about 21:15:48.5 UTC (May 25), while the camera was open. below photograph shows the brightnes speak, when it was cruising close to the Coma cluster:

click image to enlarge

IGS 1B is a defunct Japanese Radar Reconnaissance satellite. Since it went out of control, it is producing flares occasionally (sometimes up to mag. -3 to -5 peak brightness).

Galaxy 11 was flaring again, but is getting fainter at its peak. If my modelling is right, it might flare again in a new cycle around the 3rd week of July. Below link provides an animated GIF of last night covering 20 minutes with the geosat flaring up. Milstar 5 is in it as well, moving southward.

Link: animated GIF ( 5.5 Mb)

Around 22:10 UTC, Intelsat 802 (97-031A) briefly flares up close to Galaxy 11. It stays faint, but is visible. The single image below might help discern it:

click image to enlarge

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