re: Confusing satellites

Walter Nissen (dk058@cleveland.Freenet.Edu)
Thu, 9 Nov 1995 07:29:40 -0500

I note that recent messages reflect some uncertainty about the identity of 
the various pieces from the 95-59 launch. 
 
Many of us have keenly felt the difficulties which can result from 
confusion of identities, Tristan Cools perhaps most keenly of all. 
 
Confusions about the vulgar name are routine in the immediate post-launch 
period, and the timely distribution of elsets on the net to a growing 
number of observers actually increases the extent of the problem. 
 
My feelings about this are various.  I am positively thrilled that OBS are 
being reported to SeeSat-L, and would do nothing to discourage that, but 
would hope that we aren't setting ourselves up for a succession of 
identification problems. 
 
It would bring me great comfort if observers would identify satellites 
by including the elset (TLE) used to locate the object.  This practice 
would provide all three names for the object (highly desirable, in my 
view) and more particularly would allow for resolution of more profound 
ambiguities, such as the cases of Timation 1 and Sampex where US SPACECOM 
has apparently(?) provided elsets for different objects under the same 
catalog number/COSPAR id pairs. 
 
This suggestion would have the disadvantage of adding still more bulk to 
the traffic on SeeSat-L.  I am reluctant to encourage that.  I even find 
some of the .sig files quite lengthy, and I must say I find the ones which 
have low information density rather annoying, even when they achieve their 
intended purposes. 
 
Possibly, people would find it quite inconvenient to cut-n-paste the elset 
into their messages, but in this era of better and better tools, perhaps 
not too inconvenient. 
 
I solicit opinions about whether we should encourage people to provide 
elsets in cases of uncertainty about the identity of the object. 
 
I include as an appendix an e-mail message from Russell Eberst about 
confusion of identity, which I would find insightful, even if he didn't 
agree with my warning! 
 
Thanks. 
 
Cheers. 
 
Walter Nissen                   dk058@cleveland.freenet.edu 
 
P.S.  Please note that the appendix is quoted with ">"s.  A recent 
SeeSat-L message about Gary Morris' fine element-request mailing list 
apparently included a previous message without such quotes.  The header of 
that included message confused my mailer because it looked "alive", not 
"dead".  Just a reminder that messages should not include text which looks 
like a header; "From: ", "Subject: ", "To: ", "Date: " at line beginnings 
are particularly troubling. 
 
--- 
 
Data are not facts. 
Facts are not information. 
Information is not knowledge. 
Knowledge is not truth. 
Truth is not wisdom. 
 
--- 
 
> Date: Fri Oct 13 14:21:31 1995 
> From: R.Eberst@roe.ac.uk (Russell Eberst) 
> Subject: Confusing satellites 
> To: dk058@cleveland.freenet.edu (Walter Nissen), mike@comshare.com (Mike McCants) 
 
> It is very easy to confuse satellites what with the multitude 
> of objects in orbit. I try to fit in observations of as many 
> satellites as possible, as consistent with being accurate. This 
> of course involves a compromise and often completing obs on one 
> satellite, with only a minute or so before the next is due. 
> So I get the predicted R.A. and Dec and check if the azimuth and 
> elevations are increasing or decreasing i.e. if it's going 
> left to right or right-to-left and if its going up or down. 
 
>   Grabbing the binoculars, I point them where the predicts 
> indicate, and look for something going up (or down) and l>r or 
> r>l. If an object is seen that doesn't fit the expectation then 
> it is ignored, and I wait for one that does fit. Occasionally 
> I see an intruder that fits the predicts and observations are 
> made in erroneous belief that I'm looking at the right object. 
> Some of these obs are later recognised as belonging to the wrong 
> object and corrected but it wouldn't surprise me if several of 
> my archived obs are not of the reported object. 
 
>  As one example there are numerous sun-synchronous object with 
> similar R.A. of ascending node and these can easily turn up 
> close to each other. 
 
>  So we should conclude with the warning "Observers beware". 
 
> best wishes Russell