Sat Tracking Tips & Tricks

Hi Jai,

What useful data did you not record? Do you have questions on how to acquire that data, so that the timing and positions are precise enough to compute the orbit?


Yes. Knouse labs is doing research here. Many amazing possibilities for regenerative medicine, once breakthroughs are achieved.

If I understood your comment.

I blogged about it here, if you happen to be interested.

So I am preparing for (I hope) a weekend of astronomy, sats tonight, DSO tomorrow. Predictions from classfd.tle yield the following as visible and a bit to a lot old (the numbers after the IDs are uncertainty of prediction in seconds):

21809 38773/38758 28095 39462 31601 24 43145 5 25724 24 21808 28097

plus new to me’s from space track:

4594 39446 43712/714

Using trusat’s priorities prediction download,

  1. I only get 31601 and 25724 in common, which makes sense as they are the only classfd objects that are a bit old, so the others didn’t “make the cut” yet as priorities.

  2. But I don’t get the new to me’s, although to my knowledge no one has ever seen them.

  3. And I get a ton of formerly classified objects, which makes sense as we stopped tracking them on seesat.

To me,

  1. is good
  2. is explainable because we have never seen them, but is this the right way? I have a listing of what should and shouldn’t be visible if that would help
  3. is…complicated. Seesaters probably won’t care about FCO’s (formerly classified objects) any more.


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I think a quick note about satellite numbering would be useful:

NORAD (US numbering) =

1-44792 as of today, normal catalog of all objects as published by space-track. This numbering is temporally sequential; each object is numbered as it is found with next available number.

The International numbering for each is based on launch and will be

58-002B to 19-077C

e.g. 58-002B is B object from 2nd launch of 1958

Note this may lead to a situation where the 2 systems do not parse in sequence, e.g. 44792 is 98067QX, as it is a piece of debris from ISS that has just now been cataloged 21 years after launch.

81000-89496 as of today is a “analyst” catalog maintained by space track (see site for explanation)

They do not assign INTL numbers to these

The few times I have seen these, I use the number and “T” at the end for the INTL designation, I can’t remember who suggested that

You may notice a “Y2K - like” issue coming up with the numbering scheme with all the planned launches, but that is for another post…

ISON catalog:

10200-134640 as of today

The ones I see, I list as ISON with number if it overlaps NORAD

On my personal list, I add a 0 on the end if it is 5 digits to make it unique

I have assigned INTL ID of 50-XXXA to the ones I track, hoping the system will be fixed by 2050

Mike McCants’ classfd.tle:

Uses NORAD and INTL if it has been identified by analysts and observers

If unknown, uses 90xxx or 96xxx and the year + (DOY+500) + A,B,etc. for INTL

Unknown 070914
90177 07757A meaning listed in 2007 on 257th day of year, “A” object

Notice that for this one, the listing date is included in name (Sep 14 2007)

90xxx and 96xxx originated as separate lists of unknowns, I believe 90xxx was hobbyist discovered and 96xxx was based on the COGO (CLASSIFICATION OF GEOSYNCHRONOUS OBJECTS) catalog published by ESA.

Test on Friday…

@hafsnt -

Regarding #2 - the “Priorities” list currently only accounts for objects that already have TLEs in the catalog. Also, the “Priority” is simplistic at the moment - objects that have not been seen by TruSat users for 30 days (but have been seen in the last year).

Regarding #3 - is not designed for tracking only classified satellites, so we currently provide information about any object that has been observed and reported by a user. We hope to add additional features in the near term which would allow you to filter the catalog by the CelesTrack categories, as well as the NORAD object codes - to get to the objects of interest to you.

Also, with the “Proof of Satellite” algorithm concepts described in the TruSat whitepaper, we also intend to implement a much more complex “Priority” listing which takes into account the age of the TLE, the performance history of the observer, the uncertainty of the fit, among other things.

Last - another feature we have on the list, is being able to show you objects filtered by your observation location(s), but you can currently get that capability by downloading our TLEs and using third-party tools to look for opportunities.

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Very useful reply thanks. I know I am pre supposing features you were still working on, but somebody has to nudge.

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Further to the number issue, saw an ISON object tonite. Of course, using its 6 digit ISON number will not work right with IOD format:

14364619 828A 7779 G 2019112406021096 17 25 0236696+063995 16 +165 10
14364619 828A 7779 G 2019112406031096 17 25 0237381+063905 16 +159 10

Optionally, I report it as a 9999x and note its actual number:
99999 19 828A 7779 G 2019112406021096 17 25 0236696+063995 16 +165 10
99999 19 828A 7779 G 2019112406031096 17 25 0237381+063905 16 +159 10
99999 = ISON 143646

This is messy, as 9999x gets used all the time. It may be that ISON objects are not something that need to be reported, but if the are of interest, what would you suggest I do to report them?

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Just a note about real unidentified satellites. While I’d still like to figure out a way to report ISON objects that have numbers with 6 digits, there are times when I will report an actual UNID. Although these may have reused numbers such as 99999, they will have unique cospar IDs based on the formula:

19=current year
862 = DOY + 500
A = 1st one today

If for some reason there are more than one UNIDs seen in one day, use 99998, 99997 etc. and B,C etc. for the cospar ID.

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