RE: [OT] Need help in identifying a comet like object

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Wed Feb 13 2013 - 17:33:42 UTC

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    Sankar wrote:
    
    > *Ted*, can you please e-mail me the *first* TLE of the object to me (or
    > please let me know where I can get it)?
    
    I obtain my TLEs from the Space Track web site, which is operated by USSTRATCOM. I do not have a redistribution
    agreement with USSTRATCOM, so I cannot share their TLEs with you. I recommend that you obtain a Space Track account. The
    web site is here:
    
    https://www.space-track.org
    
    I offer the following note of caution, which applies regardless of your source of TLEs. Four objects from the launch
    were expected to reach orbit: two payloads, the upper stage rocket and a dual payload adaptor. USSTRATCOM has catalogued
    and reported TLEs of four objects (13006A / 39078 through 13006D / 39081); however, it is evident that they have yet to
    reliably determine which object is which. This is common in the immediate aftermath of a launch. Eventually, the
    payloads will be the A and B objects, the rocket will be C and the payload adaptor will be D. In the meantime, the
    identifiers of any given TLE cannot be taken at face value; therefore, some care is required in selecting TLEs. 
    
    Fortunately, your observation occurred shortly after all four objects reached orbit, which means they were still close
    together and in nearly the same orbit; therefore, for your purpose you can safely use the first TLE attributed to any of
    the four objects. Look for an epoch near day 13038.7, but any TLEs of epoch days 13038 and 13039 should be reliable.
    
    You can also use later TLEs, but you should use only those with mean motion close to 2.27 rev/d (the orbits of the
    rocket and the payload adaptor). One or both of the payloads have manoeuvred, and now have mean motion less than 2
    rev/d, so you should avoid those, since they no longer apply to the period of your observation.
    
    For descriptions of the data format of TLEs I recommend:
    
    http://celestrak.com/NORAD/documentation/tle-fmt.asp
    
    http://www.satobs.org/element.html
    
    Ted Molczan
    
    
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