I have just spotted STS-24 (Discovery) and its separated external tank as they crossed low across Edinburgh's brightly-twilit southern sky at about 21:22 UTC, some 20 minutes after launch. The Sun was only 4 degrees below the NW horizon and no stars were visible. The two objects were picked up by binoculars while still low in the SW and throughout the pass one object remained directly above the other with a (very approximate) separation of 0.5 degree. The lower object (I suspect the tank) was distinctly orange in hue and, for most of the pass, about 1 magnitude fainter than the upper one which may have peaked near magnitude -2 (though with no stars for comparison). As they moved towards eclipse low in the SE, though, the two became more equal in brightness and the lower object may even have become the brighter by perhaps 0.3 magnitude. According to the Spaceflight Now Mission Status page, there might have been a "post-launch dump of residual fuel from Discovery's main propulsion system" during the pass. Any plumes of outgassed material were probably swamped by the twilight. Alan -- Alan Pickup / Edinburgh / Scotland / COSPAR 2707: 55.8968N 3.1989W +208m (WGS84 datum) ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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