Unusual brightness of 96072B Titan 2nd stage
Ted Molczan (molczan@fox.nstn.ca)
Tue, 31 Dec 1996 11:49:55 -0500
Tony Beresford's observation of 13:47 UTC on 31 Dec 96
upholds the std magnitude of 2.1 that I estimated from
his and Rob McNaught's reports of 30 Dec. Prior observations
supported a std mag no fainter than 3. So this remains
a very bright object, exceeded only by Mir (1.6) and shuttles
(0.8), to the best of my knowledge.
For about the past year, I have been using a std mag of 4.82
for Titan 4 2nd stages, based on Rainer Kracht's analysis of
Russell Eberst's numerous accurate observations of 91017B. He
also analyzed 91076B, and obtained similar, though slightly
fainter results.
So it seemed reasonable to assume that all such objects would
be essentially std mag 5 objects. But the extreme brightness
of 96072B requires that this be revisited, so I asked Rainer
to update his study to include the 2 Titan 4 stages observed
earlier in 1996: 96029B and 96038B; all by Russell Eberst.
He has kindly done so, and the results, tabulated below, are
very interesting. These newer objects are considerably
brighter than 91017B 91076B. This morning, I added 90050E to
the picture, based on 19 obs, all by Russell Eberst. On
average, I found that it was about as bright as 91017B and
91076B.
So these objects are not all alike. I would not place too
much importance on the apparent trend to increasing
brightness, because the sample of 6 objects is rather small.
Object State Obs Std Mag Payload
------ -------- --- ------- -------
90050E flashing 19 4.67 NOSS
91017B flashing 124 5.14 Lacrosse
91017B steady 494 4.82
91076B flashing 52 5.33 NOSS
96029B all 87 3.74 NOSS
96038B flashing 28 3.50 SDS
96072B steady <10 2 to 3 KeyHole
One additional avenue of inquiry was suggested yesterday
by Allen Thomson:
> I wonder if pictures of the booster before or during launch would
>shed any, ah, light on the matter. IIRC, such pictures have been
>released for most T-IV launches.
I believe this is worth following-up. I would like to compare the
"paint-job" on these objects.
Clear skies and Happy New Year!
Ted Molczan