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We report on low-spectral resolution observations of comet 9P/Tempel 1 from1983, 1989, 1994 and 2005 using the 2.7m Harlan J. Smith telescope of McDonaldObservatory. This comet was the target of NASA's Deep Impact mission and ourobservations allowed us to characterize the comet prior to the impact. We foundthat the comet showed a decrease in gas production from 1983 to 2005, with thethe decrease being different factors for different species. OH decreased by afactor 2.7, NH by 1.7, CN by 1.6, C$_{3}$ by 1.8, CH by 1.4 and C$_{2}$ by 1.3.Despite the decrease in overall gas production and these slightly differentdecrease factors, we find that the gas production rates of OH, NH, C$_{3}$, CHand C$_{2}$ ratioed to that of CN were constant over all of the apparitions. Wesaw no change in the production rate ratios after the impact. We found that thepeak gas production occurred about two months prior to perihelion. Comet Tempel1 is a "normal" comet.

Placing the Deep Impact Mission into Context: Two Decades of Observations of 9P/Tempel 1 from McDonald Observatory