Impact was scheduled for 10:52 pm MST, July 3. So, while most historians and astronomy enthusiasts will recall that comet Tempel was assaulted on America's Independence Day, I and most observers in the western U.S. who watched the event will recall July 3 as the red letter day. I wanted a record of the comet's appearance immediately prior to impact and made the sketch at left at 10:40 pm MST. Even in the 18-inch Dobsonian (122X), the comet was quite faint from my backyard observing site. Tempel appears as a foggy 3' diameter patch of light, best seen while sweeping the area. No nuclear condensation (pseudo-nucleus) is visible. The three stars immediately to the northeast range in brightness from 11.2 magnitude to 11.9 magnitude. Another 11 stars dot the field.

About 5 minutes after impact, I noticed an intermittent stellaring that seemed to lie within the comet's coma. After another 5 minutes--10 minutes total post-impact--this nuclear condensation was constantly visible under direct gaze. At 11:12 pm MST (06:12 UT, July 4), I noted an apparent brightening of the southeast portion of the coma. Nine minutes later at 11:21 pm MST (06:21 UT), I noted a slightly more diffuse appearance of pseudo-nucleus. Shortly afterwards, the comet slipped behind some trees and my observing session was ended.

The sketch at left records the various but subtle changes I noted in comet Tempel's appearance over the roughly 30 minutes I was able to observe following impact. The comet has moved a bit to the southeast. The stellaring or pseudo-nucleus is seen just inside the northwest edge of the coma. By my estimate this stellaring at the core never quite equalled the faintest of the three stars to the northeast. So, my very rough estimate would put the nuclear condensation at an m2 of mid-12th magnitude.

In the days since Deep Impact's successful conclusion, some visual observers have reported seeing a brightening of the comet at the moment of impact. I find such reports highly dubious, at least with respect to claims of seeing an actual flash from the impact. One needs to keep in mind that it is impossible to see the actual comet in amateur telescopes. What we can see is the bright coma surrounding the comet. Even a stellar pseudo-nucleus is the bright, inner coma shrouding the comet. In this context, reports of a visually detectable brightening at the moment of impact should be held with skepticism until photometric data is published, giving us an objective record of comet Tempel's response to being shot by an 820-lb. bullet.