EGP, VISUAL.TLE, Mir the spaceship, marketing genius

Walter Nissen (dk058@cleveland.Freenet.Edu)
Fri, 5 Jul 1996 08:16:24 -0400

cc: Mike McCants, Rainer Kracht, Russell Eberst, Victor Slabinski 
 
Jay Respler, 
 
As you may remember, I earlier suggested that you might wish to include 
EGP = Ajisai = 16908 = 86- 61 A in VISUAL.TLE.  You responded that it is 
too faint. 
 
QUICKSAT.MAG supports your claim: 
> 16908   86 61A    EGP             3.5  2.2 0.0 0.0 3.6 
> flashes to 4th or 5th mag 
 
I wish to bring the following to your attention. 
 
Minoru Sasaki and Hidekazu Hashimoto, in "Launch and Observation Program 
of the Experimental Geodetic Satellite of Japan" in IEEE Transactions on 
Geoscience and Remote Sensing", Vol GE-25 (1987), #25, p529, provide a 
theoretical model for the brightness of Ajisai, giving an equation I = 
gamma*I[s]*a*a*T/(4*r*r), m[s] = -2.5 log I[s] = -26.8, gamma = .85, a = 
8.5 m, T = exp (-k sec z).  They give a table of stellar magnitudes for 
Ajisai for ranges from 1.5 to 2.9 Mm and .3 < k < .5 (not good to good 
atmospheric transparency) with values from 1.44 to 4.15. 
 
I haven't followed their argument, nor checked their math, nor do I expect 
you to be able to follow their argument from this thumbnail sketch 
(assuming it is self-contained, an assumption I haven't checked, the whole 
argument occupies half a page).  However, I find it interesting that their 
theoretical results coincide closely with my observations, and, 
apparently, do not support the observations of others (at least you and 
Mike McCants).  Ajisai varies pretty wildly from time to time within a 
single pass and also at different passes.  But at its best, I think I am 
seeing 1st magnitude flashes, albeit of very short duration. 
 
I know what I am seeing.  I can only guess what impact this may have on 
your thoughts about the suitability of Ajisai for VISUAL.TLE.  Certainly 
it is invisible much of the time.  Equally certainly, it is an object of 
extremely high interest to beginning visual observers, because at special 
and frequent moments it overcomes its usual invisibilty.  Based on my 
observing experience, I find it really, really difficult to believe that 
there are more than 100 satellites of greater interest, though I have to 
admit there might possibly be 100 that are easier to find, because you may 
have to exercise some patience from a typical, badly polluted sky. 
 
 
I haven't achieved the results of Ron Dantowitz, as impressively displayed 
in the August Sky&Telescope, but on June 23rd I picked up Mir = 16609 = 
86- 17 A near zeta Leo in my 67x203 monocular and followed it, very 
jerkily by hand, for a minute, observing an angular structure, and, for 
the first time, experienced a palpable sense of watching the flight of a 
spaceship.  I think it likely that he is forging an important future 
direction for tracking. 
 
 
Cheers. 
 
Walter Nissen                   dk058@cleveland.freenet.edu 
 
 
P.S.:  There are a few other, more conventional choices you might want to 
add to VISUAL.TLE (actually it's called visual.txt in the Web access at 
http://www.grove.net/~tkelso): 
C* 1844 r 
C* 2278 r 
Resurs 1-3 r 
C* 2297 r 
C* 2313 
C* 2322 r 
C* 2326 
 
P.P.S:  My correspondence backlog has never been as bad as now, and I 
apologize to all of you to whom I owe the courtesy of a reply. 
 
P.P.P.S:  A few other tidbits from the Sasaki and Hashimoto article:  The 
mirrors are not planar, as I previously said.  They have a radius of 
curvature of 8.4 to 9 m.  They estimate the duration of a flash as 5 ms 
and the half-life of the spin-rate at 78 years. 
 
--- 
 
Marketing consultant:  Someone smart enough to extract thousands of $ from 
seemingly sensible business executives by inducing them to send out millions 
of messages to their best customers which read, in pertinent part: 
Bad news:  You didn't win, loser.  You lost.  Again. 
Good news:  We're really so sorry for imposing this unpleasantness on you.