Re: NOAA 15
Sue Worden (worden@fc.net)
Mon, 4 Oct 1999 21:00:57 -0500 (CDT)
Don Gardner wrote:
> The NOAAs, like the DMSPs will flare unpredictably from time to time
Speaking of DMSPs...
Ed Cannon, Mike McCants, and I observed a spectacular magnitude zero
flare from DMSP B5D1-3 (10820/78-42A) at about 1999-10-02 01:45 UTC,
just past culmination on a north-to-south pass high across the west.
Several seconds prior to the flare, I observed a very sharp specular
"glint" from this DMSP to approximately magnitude +2 through my 10x50
binoculars.
This DMSP was also flashing irregularly on both sides of these events.
My stopwatch data indicate that the period was about 6 seconds before
culmination, increasing to about 8 seconds after the flare. However,
I observed NO triplet of semi-equally-spaced flashes throughout the
entire pass. I.e., all of my "split times" flash period data points
are wildly different, though they appear to all be multiples of about
6 or about 8 seconds.
Note that the "glint" mentioned above was quite different in character
from the regular flashes. It was definitely what I call a "glint" as
opposed to being a mere "flash".
But I would like to avoid another discussion on this list of "when is
a flash a flare or a glint"... Below is what I use to subjectively
discriminate amongst them, and if you disagree, you can simply use
this table to translate my terminology into that of your own choosing:
Duration in Time Spatial Extent d(brightness)/d(time)
Glint very brief very small very "steep" slope
Flash brief small "moderate" to "steep" slope
Flare "extended" "extended" "flat" slope
Getting past those asides, later that same evening, we also observed a
flare from NOAA 15 (25338/98-30A) just past its culmination.
QuickSat output for both passes:
30.310 97.881 920. BCRC (Nike Site) 2000 15.0 15 F F T T T
*** 1999 Oct 1 Fri evening *** Times are PM CDT *** 20 0 642
H M S Tim Al Azi C Dir Mag Dys F Hgt Shd Rng EW Phs R A Dec
10820 DMSP B5D1-3 78 42A 6.4 1.7 6.9 3.9 S 4.5
8 43 14 0.0 52 336 316 5.3 3 1 492 315 604 1.5 92 1745 61.5
8 43 46 0.0 61 315 297 5.1 3 1 493 318 555 1.6 94 1751 47.5
8 44 18 0.0 64 282 C 267 5.1 3 1 493 320 540 1.6 96 1753 31.9
8 44 50 0.0 59 250 238 5.2 3 1 493 323 562 1.6 97 1755 16.5
8 45 22 0.0 51 232 222 5.4 3 1 493 327 616 1.5 98 1755 2.9
25338 NOAA 15 98 30A 6.0 2.0 24. 3.8 S 4.0
9 11 35 0.0 40 230 68 5.4 3 2 508 232 734 1.2 99 1756 -5.7
9 12 8 0.0 44 246 79 5.3 3 2 508 247 696 1.2 103 1736 5.1
9 12 41 0.0 44 264 C 93 5.3 3 2 508 263 687 1.1 107 1712 16.5
9 13 14 0.0 42 281 106 5.5 3 2 508 278 708 1.1 111 1645 27.3
9 13 47 0.0 38 295 116 5.7 3 2 509 294 756 1.0 114 1614 36.7
--Sue Worden (worden@fc.net)