M27
MPC OSERVATORY 643
Astronomical Research
Dedicated to expanding human knowledge
Saturn
DEEP IMPACT/TEMPEL 1 RESULTS
Stack
This image is a combination, or stack, of many images in order to show Tempel 1 brightening.  The telescope was tracking the stars, and the comet moved diagonally toward the upper right corner.  The images in this composite cover from 18 minute before, until 30 minutes after, the impact. The coma brightening is visible.
We monitored the July 3, 2005 event from Joshua Tree National Park in Southern California from 9:58 PM - 11:55 PM PDT.  Excellent seeing conditions compensated for the low viewing altitude, and we were able to collect data that recorded the brightening from the collision of NASA's Deep Impact probe with comet Tempel 1 as it happened.

Our "amateur" CCD images provide continuous coverage for the 2-hour period centered on the Tempel 1 - Deep Impact event, and distinctly show a brightening of the coma around the nucleus which began immediately after impact and continued to increase for about 45 minutes before levelling off.  We measure a change of 1.85 mV in the m1 magnitude of the comet, approximately a 4.7-fold increase in brightness, of the nucleus and coma!
Captions for images below include image number, time (PDT), minutes from impact, and m1 (coma magnitude) in V.
T1004
#1004 - 10:49:48 PM (T - 2) 15.23V
T1008
#1008 - 10:52:26 PM (T - 0) 14.90V
T1013
#1013 - 10:56;06 PM (T + 4) 14.35V
T1031
#1023 - 11:02:43 PM (T + 11) 15.23V
T1043
#1031 - 11:08:05 PM (T + 16) 13.79V
T1052
#1043 - 11:16:00 PM (T + 24) 13.36V
Follow these images from left to right, top to bottom.  These false-color images emphasize the brightening of the coma due to the impact of NASA's Deep Impact probe. 
Graph
We collected images every 40 seconds during the 2-hour period centered on the event.  Based on 7 images immediately prior to impact the coma m1 measured 15.17V.  The coma began to brighten immediately upon impact, climbing to ~13.8V within just 15 minutes.  The brightening began to taper, reaching ~13.4V about 31 minutes after impact.  An analysis of 7 images taken 1 hour after the impact show it had stabilized at m1 = 13.32V.