It's tough for me to estimate a brightness change as I couldn't see the nuclear region prior to impact. But at its brightest (about 15 to 20 minutes after impact), the nuclear region appeared stellar and similar in brightness to the faintest of the three stars just northeast of Tempel. Those three stars were... Tycho 5546:1273:1, 11.2 mag. GSC 5546:1397, 11.6 mag. GSC 5546:0882, 11.9 mag. NOTES: - ID's from MegaStar5 - Magnitudes from ASAS-3: _http://www.astrouw.edu.pl/~gp/asas/asas3_catalog.html_ (http://www.astrouw.edu.pl/~gp/asas/asas3_catalog.html) Thanks to Brian Skiff for pointing me to ASAS-3 So, I'd ballpark--large stadium w/ corporate skyboxes--the core at the upper 11th magnitude range. Who else made comparisons between the core and those three stars and what were your results? For about 5 minutes, they formed a fine parallelogram asterism. Regards, Bill in Flagstaff -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.