[meteorite-list] Deep Impact

[MexicoDoug at aol.com]

>I wrote:

>> NASA reports have visual confirmation via downloaded data  of  impact
>> just 5 minutes after the officially confirmed impact at  52 minutes after 
>> the hour.   The light needs close to 7 minutes 26  seconds to get to  JPL.
>> Was impact really earlier or have I missed something?  
>> This is important for backyard amateurs to know who followed  the event.

Ron Kindly Answered:
 
>Both times are in Earth-Receive time, which means it already  includes
>the one-way light time.  The impact occurred at 10:52 PM PDT ERT, 
>which we could tell when we lost the signal from the impactor. Of  course,
>the impact really occurred 7+ minutes before that, but it took that  long 
for 
>the signal to reach Earth.  Five minutes later at 10:57 PM PDT  ERT, we 
>received the first image from the flyby spacecraft confirming the  impact.
 
It is nice to know that impact actually happened at 10:45 PM PDT.   Thank you 
very much for that clarification, Ron.  Somehow I never saw PDT  ERT's used 
anywhere in the press, or on the official websites anywhere.  So  now I have 
the embarrassing task of explaining to all the folks I brought out at  night 
that in fact, impact light would not reach us at 11:00:00 PM PDT as I so  car
efully and foolishly explained, and that when we held our breaths and said a  few 
words at impact time, that it was already 7.4 minutes past... Oh well, now I  
have to take my licks on this one.    I lost almost 2 degrees of  important 
elevation (15 vs. 17 degree alt)-not thatit would have mattered it  turned out-, 
and my armtwisted wary team an extra 8 minutes of sleep (that  mattered to 
them)....Yes I now see that on the Deep Impact Website that is  prominently 
hidden in the table of highlights. :-(
Doug