More flashes (Iridium 20, Raduga 33, NOAA 7, Spot 3)
Ed Cannon (ecannon@mail.utexas.edu)
Sat, 20 Jun 1998 15:56:31 -0400
Here are some Friday evening (early 20 June) observations from
30.314N, 97.866W, about 280m.
Iridium 20 (24871) -- We didn't get to the site in time for Mike
to set up his telescope so as to see its first (twilight) pass,
and we did not see any flashes using one-power. On its second
pass, there were negative mag. flashes at either 4:00:44, 46, 49,
and 50 (or 4:00:40, 42, 45, and 46, as I'm not sure now if those
were or were not the actual times on my 4-second-slow clock.)
Then around (before and/or after) 4:03:40, for quite a number of
seconds, Mike observed it telescopically, and it was tumbling
every *one-half second*. I'm not sure what the magnitude was.
(My notation is legible but too cryptic. Please pardon me for
being so disorganized! I can see where an audio recording could
be very helpful -- except for the fact that it would require
having time after observing to play it back and transcribe the
data....)
Raduga 33 (23794, 96-10A) -- a -2 flash at 2:31:37 (or 41) and a
+1 flash at 2:31:50 (or 54)
NOAA 7 (12553, 81-59A) -- some one-power flashes around 3:34:00
(WWV time)
Spot 3 (22823, 93-61A) -- Wow! Individual negative mag. flashes
at 3:53:45 (or 49) and 3:56:01 (or 05), with other series of
one-power flashes at about (and here I do have the right times,
plus-or-minus about one second) 3:52:12, 22, 32, and 44, and at
3:55:08, 20, and 32.
Someone asked about an image of Spot 3. From the illustrations
that I could find, it must be solar panels reflecting from Spot 3.
At least, I don't see anything else that looks like it could
produce such bright reflections. Here are the images that I was
able to find:
two versions of the same illustration (may be Spot 1):
small
http://msl.jpl.nasa.gov/QuickLooks/pictures/spot1.gif
a little larger
http://hdsn.eoc.nasda.go.jp/guide/guide/satellite/satdata/image/spot.gif
a small but nice illustration of a Spot 1, 2, and/or 3 satellite
observing the Earth's surface. (The server seems a bit unreliable.)
http://www.cnes.fr/images/icones/spot.gif
another small, very simple illustration of how a Spot satellite
observes the Earth:
http://edcwww.cr.usgs.gov/glis/graphics/guide/spot/spot_nadir.gif
The Spot 4 home page is:
http://spot4.cnes.fr/
but it appears that Spot 4 is differently configured the 1, 2, and 3.
Ed Cannon -- ecannon@mail.utexas.edu -- Austin, Texas, USA