yet more iridium 27 strobes

richard.keen@kingsmarket.com
Sun, 04 Jan 98 20:54:30

                                  
  Thanks to recent postings on Seesat about Iridium 27, I gave it a look
tonight (Jan. 5 UT).  First, here's the Quicksat output for this pass:
  1998 Jan 5  Mon  UT  043 1330
   H  M  S Tim Al AziC Dir  Mag Dys F  Hgt Shd  Rng  R A  Dec Name
   1  8 23  .1 89  95C 272  5.3  12 4  351 218  351  111 39.6 Iridium 27
  Using 7x50 binoculars, I first acquired the object at culmination (virtually
overhead) just below (east of) the Andromeda Galaxy.  It was irregularly
variable in brightness, mostly between magnitude 6 and 7, with some hint of
brief flashes to magnitude 5.  As it headed north and lower, the flashes
became more apparent, and as its elevation decreased to about 60 degrees, the
flashes became naked eye at about magnitude 4, and were occurring every 3
seconds (roughly times by counting one-thousand-one, etc.).  The flashes
continued as it passed a couple degrees east of Polaris, and increased in
brightness.  At an elevation of about 30 degrees (azimuth about 5 degrees) the
flashes peaked at magnitude -3.  There were two such flashes, and then they
faded rapidly.  By 20 degrees elevation the flashes were back to 5th
magnitude, even in 7x50 binoculars.
  The "ramp up" of the flashes from magnitude 4 to magnitude -3 was only about
8 flashes, and the "ramp down" was even fewer flashes.
  Thanks to all for pointing out this dramatic object.
  Cheers, Rich Keen
  Coal Creek Canyon, Colorado, USA (39.877N, 105.391W, elevation 2728m)