[meteorite-list] Deep Impact

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Tue Jul 5 20:07:11 2005
Message-ID: <8b.2aaed5c2.2ffc7aa5_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
Received on Tue 05 Jul 2005 08:07:01 PM PDT