George Olshevsky wrote: > >>The last reboost was on 9/15/2005<< > > Hey, that would give the ISS three whole days to accumulate a > substantial schedule difference before its "scheduled appearance" over > San Diego on 9/18. I started looking for it about 15 minutes before > 8:15 pm and went inside about 15 minutes after 8:15. Could it have > been more than 15 minutes ahead of/behind schedule simply due > to the reboost? According to my calculations, the reboost on Sep 15 was too small to account for your having missed the object. I used elsets as old as 6 days and as recent as a few hours, and obtained substantially the same prediction as Heavens-Above. A few seconds before 20:15 PDT, it passed near the end-star of the handle of the Big Dipper. This was about 29 deg above the NW horizon. A little over one minute later is passed near Vega, about 81 deg above the western horizon. If you kept your eye moving back and forth along the path between those stars, during this period, you should easily have spotted ISS. We will probably never be able to determine precisely why you did not see it, but there may be clues in this comment you made in an earlier post: <<<< I began watching shortly before 8 pm Sunday night, eyes glued to the NW, 11x80 binoculars strapped around my neck. When my watch said 8:15 and no sign of the ISS I began to wonder what was going on. I did spot a few airliners and a helicopter during my little vigil, and to amuse myself scanned the moon's face as it slowly climbed upward from the horizon. >>>> Sounds like after waiting 15 min for the big event, you became a bit antsy when the object did not appear at 8:15 PM PDT, as predicted. This may have adversely affected your concentration, even caused you too take your eyes off the predicted path - just long enough to miss it. Remember, it covers a lot of sky in even 30 s. If, as many folks do, you allow your wristwatch to run fast, by even 30 s, then that could have contributed to your feeling that the object was overdue, causing you to turn away too soon and just long enough to miss it. In any case, there will be many more good ISS passes, and I wish you well observing them. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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