TiPS, NASA Select, local time errors, munging elsets

Walter Nissen (dk058@cleveland.Freenet.Edu)
Tue, 27 May 1997 08:20:02 -0400 (EDT)

Craig Cholar, 3432P@VM1.CC.NPS.NAVY.MIL, writes: 
> Subject: re: TiPS's NORAD# 
> The TiPS personnel at the Navy Research Lab are eager to hear from 
> TiPS observers. 
> >Also, if you're in touch with others that regularly 
> >observe TiPS, we'd appreciate hearing from them also if they notice 
> >anything unusual going on with the tether. 
Considering there have been maybe a hundred messages posted here on 
SeeSat-L about TiPS, including a (mostly) unutilized proposal (from me) 
for a format for reporting orientation, it would be interesting to know 
whether these personnel are reading SeeSat-L. (jim hale) writes: 
> Subject: STS Sonic boom 
> The map showing the path of Atlantis on NASA Select TV showed the STS 
> over Georgia at the moment I heard it...  Strange. 
> Perhaps I heard something else, as I'm located in northern Arkansas 
> a fair distance from Ga. 
> I had expected to hear it when it was closer to overhead, or a little 
> past me. Georgia is WAY past me.   Jim Hale  93.47W  35.75N  2200' 
This message illustrates to me how important it is to use some judgment in 
determining topicality for SeeSat-L.  Literally, I suppose Jim Hale would 
have had to be watching one of those silly, multi-colored light boxes to 
make this a "visual observation" :-)  Since he probably wasn't watching 
such a box, a literal interpretation might find it to be off-topic. 
But I think it is clearly on-topic, because it relates strongly to the 
vital need for visual observers to know how accurate the information they 
are receiving from NASA Select is.  I hope those of you who can shed some 
light on this subject, including prior missions, will share your thoughts 
and records with SeeSat-L. 
For SeeSat-L, as for any forum, it is virtually always appropriate to 
query those responsible about any "marginal" topic you may wish to 
discuss.  I'm sure I speak for Bart, when I say that both of us welcome 
e-mail inquiries about the appropriateness of any material for SeeSat-L. 
Craig Cholar, 3432P@VM1.CC.NPS.NAVY.MIL, writes, er, blurts out: 
> Subject: Re: Norad 23907 MIA (correction) 
> A short time ago I blurted out... 
> >I observed #23907 NOSS 2-3 Rk Saturday night (May 25), using elset 
> >97114 from the Molczan file.                      -- 
> To clarify what I meant, locally it was May 24, and May 25 using UTC. 
> Sleepily yours, 
In an international forum like this, local time has very limited utility, 
since it is always "wrong" for most readers.  It is very important to 
provide UTC for all observations.  (Obviously, an exception is made for 
people who don't know how to determine UTC by listening to WWV, JJY, BBC 
(despite being identified as GMT, the 6 pips have actually been pipped in 
UTC for some years now), etc., using GPS, 1-900-410-TIME, etc.).  I 
encourage people to report the local time for observations, if they know 
it, so that any possible conversion error can be detected, but I would not 
encourage this for people who work in UTC (I'm more likely to get the 
local time wrong than the UTC; since I select UTC as the local time in all 
programs, I don't have to worry about resetting the time in my computer 
twice a year). 
Craig Cholar, 3432P@VM1.CC.NPS.NAVY.MIL, writes: 
> Subject: Re: Norad 23907 MIA 
> Have the observations over the past few days, taken together, provided 
> enough information for a new elset to be created, or do the observations 
> need to be more precise?  I've never tried to modify elements to make them 
> fit observations, so excuse my ignorance on this subject. 
Usually, and especially for unpowered craft, the largest problem by far is 
a bad value for ndot/2 (and correspondingly for bstar).  When the 
satellite is late, you can make it a little smaller (hopefully your 
software won't gripe about the (obsolete) checksum being wrong now) and 
tweak it until predictions generated by the elset roughly match your 
observations.  I do this pretty often and generally find it works very 
Walter Nissen 
-81.8637, 41.3735, 256 m elevation.


How come the oddest prime is even?