很奇怪的问题

昨晚预报有一颗铱星经过常德发出铱闪
以下是预报：Clicking on the time of the flare will load another page with more details,
including a map showing the track of the flare along the ground, and the
location of the nearest point of maximum intensity.

Search Period Start:	14:20, Thursday, 08 April, 2010
Search Period End:	15:20, Saturday, 10 April, 2010
Observer's Location:	Changde ( 29.0330°N, 111.6830°E)
Local Time:	China Standard Time (GMT + 8:00)

Date	Local Time	Intensity ( Mag)	Alt.	Azimuth	Distance to flare centre	Intensity at flare centre (Mag.)	Satellite
09 Apr	19:27:10	-9	64°	149° (SSE)	2.6 km (E)	-9	Iridium 94

可见亮度可到-9等，但是在预报时间，本地两个地点均未见到这个闪光，以往都从没有出现过这种情况，不知道其它地区在往日观测铱闪时有没有出现过这种“失约”的现象？